Greg is a beginner bodybuilder. Today the gym coach gave him the training plan. All it had was n integers a_1, a_2, ..., a_{n}. These numbers mean that Greg needs to do exactly n exercises today. Besides, Greg should repeat the i-th in order exercise a_{i} times.

Greg now only does three types of exercises: "chest" exercises, "biceps" exercises and "back" exercises. Besides, his training is cyclic, that is, the first exercise he does is a "chest" one, the second one is "biceps", the third one is "back", the fourth one is "chest", the fifth one is "biceps", and so on to the n-th exercise.

Now Greg wonders, which muscle will get the most exercise during his training. We know that the exercise Greg repeats the maximum number of times, trains the corresponding muscle the most. Help Greg, determine which muscle will get the most training.


-----Input-----

The first line contains integer n (1 ≤ n ≤ 20). The second line contains n integers a_1, a_2, ..., a_{n} (1 ≤ a_{i} ≤ 25) — the number of times Greg repeats the exercises.


-----Output-----

Print word "chest" (without the quotes), if the chest gets the most exercise, "biceps" (without the quotes), if the biceps gets the most exercise and print "back" (without the quotes) if the back gets the most exercise.

It is guaranteed that the input is such that the answer to the problem is unambiguous.


-----Examples-----
Input
2
2 8

Output
biceps

Input
3
5 1 10

Output
back

Input
7
3 3 2 7 9 6 8

Output
chest



-----Note-----

In the first sample Greg does 2 chest, 8 biceps and zero back exercises, so the biceps gets the most exercises.

In the second sample Greg does 5 chest, 1 biceps and 10 back exercises, so the back gets the most exercises.

In the third sample Greg does 18 chest, 12 biceps and 8 back exercises, so the chest gets the most exercise.

Difficulty: EASY

Solutions:
num = int(input())
k = list(map(int, input().split()))
chest = 0
bicep = 0
back = 0
for x in range(0, num):
	if x % 3 == 0:
		chest = chest + k[x]
	if x % 3 == 1:
		bicep = bicep + k[x]
	if x % 3 == 2:
		back = back + k[x]
if chest > bicep and chest > back:
	print('chest')
elif bicep > chest and bicep > back:
	print('biceps')
elif back > chest and back > bicep:
	print('back')


n = int(input())
a = list(map(int, input().split()))
g = 0
b = 0
s = 0
count = 0
for i in a:
	count += 1
	if count > 3:
		count = 1
	if count == 1:
		g = g + i
	if count == 2:
		b = b + i
	if count == 3:
		s = s + i
if g > b and g > s:
	print('chest')
elif b > s:
	print('biceps')
else:
	print('back')


n = int(input())
r = input()
r = [int(x) for x in r.split()]
ch = sum(r[::3])
bi = sum(r[1::3])
ba = sum(r[2::3])
if ch > bi and ch > ba:
	print('chest')
elif bi > ch and bi > ba:
	print('biceps')
else:
	print('back')


n = int(input())
arr = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
for i in range(n + 2 // 3):
	j = 3 * i
	k = 3 * i + 1
	l = 3 * i + 2
	if j < n:
		chest += arr[j]
	if k < n:
		biceps += arr[k]
	if l < n:
		back += arr[l]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
y = 0
(c, b, ba) = (0, 0, 0)
if n % 3 == 0:
	k = n // 3
else:
	k = n // 3
	u = n % 3
	if u == 1:
		c = l[-1] + c
	elif u == 2:
		c = l[-2] + c
		b = l[-1] + b
for i in range(k):
	c = c + l[y]
	b = b + l[y + 1]
	ba = ba + l[y + 2]
	y = y + 3
k = max(c, b, ba)
if k == c:
	print('chest')
elif k == b:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
count = 1
(chest, biceps, back) = (0, 0, 0)
for i in range(len(a)):
	if count == 1:
		chest += a[i]
		count += 1
	elif count == 2:
		biceps += a[i]
		count += 1
	elif count == 3:
		back += a[i]
		count = 1
if chest > biceps and chest > back:
	print('chest')
if biceps > chest and biceps > back:
	print('biceps')
if back > chest and back > biceps:
	print('back')


n = int(input())
l = [int(i) for i in input().split()]
a = [0, 0, 0]
for i in range(n):
	if i % 3 == 0:
		a[0] += l[i]
	if i % 3 == 1:
		a[1] += l[i]
	if i % 3 == 2:
		a[2] += l[i]
if a.index(max(a)) == 0:
	print('chest')
if a.index(max(a)) == 1:
	print('biceps')
if a.index(max(a)) == 2:
	print('back')


n = int(input().strip())
T = list(map(int, input().strip().split(' ')))
R = ['chest', 'biceps', 'back']
A = [0] * 3
for x in range(len(T)):
	A[x % 3] += T[x]
print(R[A.index(max(A))])


e = {0: 'chest', 1: 'biceps', 2: 'back'}
n = int(input())
m = input().split(' ')
m = [int(i) for i in m]
l = [0, 0, 0]
for i in range(n):
	if i % 3 == 0:
		l[0] += m[i]
	elif i % 3 == 1:
		l[1] += m[i]
	elif i % 3 == 2:
		l[2] += m[i]
max = 0
for i in l:
	if i > max:
		max = i
for i in range(0, 3):
	if max == l[i]:
		print(e[i])
		break


n = input()
mas = list(map(int, input().split()))
sm = [sum(mas[::3]), sum(mas[1::3]), sum(mas[2::3])]
ans = ['chest', 'biceps', 'back']
print(ans[sm.index(max(sm))])


n = int(input())
a = list(map(int, input().split()))
c = 0
bi = 0
b = 0
for i in range(1, n + 1):
	if i % 3 == 1:
		c += a[i - 1]
	elif i % 3 == 2:
		bi += a[i - 1]
	else:
		b += a[i - 1]
m = max(c, bi, b)
if c == m:
	print('chest')
elif bi == m:
	print('biceps')
else:
	print('back')


n = int(input())
k = list(map(int, input().split()))
count1 = 0
count2 = 0
count3 = 0
max = 0
temp = 0
for i in range(0, len(k), 3):
	count1 += k[i]
	if count1 > max:
		max = count1
		temp = 'chest'
for i in range(1, len(k), 3):
	count2 += k[i]
	if count2 > max:
		max = count2
		temp = 'biceps'
for i in range(2, len(k), 3):
	count3 += k[i]
	if count3 > max:
		max = count3
		temp = 'back'
print(temp)


exer = [0, 0, 0]
n = int(input())
ls = list(map(int, input().split()))
for i in range(n):
	exer[i % 3] += ls[i]
ind = exer.index(max(exer))
if ind == 0:
	print('chest')
elif ind == 1:
	print('biceps')
else:
	print('back')


n = int(input())
arr = list(map(int, input().split()))
c = sum(arr[::3])
b = sum(arr[1::3])
ba = sum(arr[2::3])
res = max(c, b, ba)
if res == c:
	print('chest')
elif res == b:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
a = l[0::3]
b = l[1::3]
c = l[2::3]
if sum(a) > sum(b) and sum(a) > sum(c):
	print('chest')
	exit()
elif sum(b) > sum(a) and sum(b) > sum(c):
	print('biceps')
	exit()
else:
	print('back')
	exit()


strength = {}
strength['chest'] = 0
strength['biceps'] = 0
strength['back'] = 0
n = int(input())
number_list = list(map(int, input().split()))
for i in range(0, n, 3):
	strength['chest'] = strength['chest'] + number_list[i]
for i in range(1, n, 3):
	strength['biceps'] = strength['biceps'] + number_list[i]
for i in range(2, n, 3):
	strength['back'] = strength['back'] + number_list[i]
max = strength['chest']
to_print = 'chest'
for (key, value) in strength.items():
	if value > max:
		max = value
		to_print = key
print(to_print)


a = int(input())
lis = list(map(int, input().split()))
c = 0
b = 0
ba = 0
for i in range(a):
	if i % 3 == 0:
		c += lis[i]
	elif i % 3 == 1:
		b += lis[i]
	else:
		ba += lis[i]
ans = max(c, b, ba)
if c == ans:
	print('chest')
elif b == ans:
	print('biceps')
else:
	print('back')


a = int(input())
l = list(map(int, input().split()))
x = 0
y = 0
z = 0
for i in range(a):
	d = i % 3
	if d == 0:
		x = x + l[i]
	elif d == 1:
		y = y + l[i]
	else:
		z = z + l[i]
if x > y and x > z:
	print('chest')
elif y > x and y > z:
	print('biceps')
else:
	print('back')


n = int(input())
lst = list(map(int, input().split()))
a = lst[::3]
b = lst[1::3]
c = lst[2::3]
m = max(sum(a), sum(b), sum(c))
if m == sum(a):
	print('chest')
elif m == sum(b):
	print('biceps')
elif m == sum(c):
	print('back')


input()
data = [int(i) for i in input().split()]
ex = {}
ex['chest'] = sum(data[::3])
ex['biceps'] = sum(data[1::3])
ex['back'] = sum(data[2::3])
print(max(ex, key=ex.get))


a = int(input())
b = list(map(int, input().split()))
c = sum(b[::3])
d = sum(b[1::3])
e = sum(b[2::3])
if c > d and c > e:
	print('chest')
elif d > c and d > e:
	print('biceps')
else:
	print('back')


n = int(input())
exercise = list(map(int, input().split()))
res = [0, 0, 0]
for i in range(len(exercise)):
	res[i % 3] += exercise[i]
if res[0] >= res[1] and res[0] >= res[2]:
	print('chest')
elif res[1] >= res[0] and res[1] >= res[2]:
	print('biceps')
else:
	print('back')


n = int(input())
line = str(input()).split()
turn = 0
note = [0, 0, 0]
for it in line:
	note[turn] += int(it)
	if turn < 2:
		turn += 1
	else:
		turn = 0
print(['chest', 'biceps', 'back'][note.index(max(note))])


n = int(input())
training = [int(i) for i in input().split(' ')]
chest = sum(training[::3])
biceps = sum(training[1::3])
back = sum(training[2::3])
train = {'biceps': biceps, 'chest': chest, 'back': back}
max_v = 0
max_k = 0
for (k, v) in train.items():
	if v > max_v:
		max_k = k
		max_v = v
print(max_k)


n = int(input())
l1 = []
l = list(map(int, input().split(' ')))
l2 = ['chest', 'biceps', 'back']
for i in range(0, 3):
	c = 0
	while i < n:
		c = c + l[i]
		i = i + 3
	l1.append(c)
print(l2[l1.index(max(l1))])


n = int(input())
exeList = [int(i) for i in input().split()]
(ches, bice, back, i) = (0, 0, 0, 0)
while i < n:
	if i < n:
		(ches, i) = (ches + exeList[i], i + 1)
	if i < n:
		(bice, i) = (bice + exeList[i], i + 1)
	if i < n:
		(back, i) = (back + exeList[i], i + 1)
print('chest' if ches == max(ches, bice, back) else 'biceps' if bice == max(bice, back) else 'back')


n = int(input())
l = list(map(int, input().split()))
c = 0
bi = 0
ba = 0
for i in range(0, n, 3):
	c = c + l[i]
	if i + 1 < n:
		bi = bi + l[i + 1]
	if i + 2 < n:
		ba = ba + l[i + 2]
if c > bi and c > ba:
	print('chest')
elif bi > c and bi > ba:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
for i in range(len(l)):
	if i > 2:
		l[i % 3] = l[i % 3] + l[i]
c = l.index(max(l))
if c == 0:
	print('chest')
elif c == 1:
	print('biceps')
else:
	print('back')


n = int(input())
x = [int(i) for i in input().split()]
chest = 0
bicep = 0
back = 0
for i in range(n):
	if i % 3 == 0:
		chest += x[i]
	elif i % 3 == 1:
		bicep += x[i]
	elif i % 3 == 2:
		back += x[i]
y = [chest, bicep, back]
m = max(y)
if m == chest:
	print('chest')
elif m == bicep:
	print('biceps')
elif m == back:
	print('back')


n = int(input())
arry = [int(f) for f in input().split()]
n = 1
(back, biceps, chest) = (0, 0, 0)
for i in range(0, len(arry)):
	if n % 3 == 0:
		back = back + arry[i]
		n = 1
	elif n % 2 == 0:
		biceps = biceps + arry[i]
		n += 1
	else:
		chest = chest + arry[i]
		n += 1
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


number = input()
lessons = input()
chest = 0
biceps = 0
back = 0
for i in range(0, int(number)):
	if int(number) - (i * 3 + 1) >= 0:
		chest += int(lessons.split(' ')[i * 3])
	if int(number) - (i * 3 + 2) >= 0:
		biceps += int(lessons.split(' ')[i * 3 + 1])
	if int(number) - (i * 3 + 3) >= 0:
		back += int(lessons.split(' ')[i * 3 + 2])
if chest > biceps and chest > back:
	print('chest')
elif back > biceps and back > chest:
	print('back')
else:
	print('biceps')


(n, exercises, aux) = (input(), map(int, input().split()), [0] * 3)
for (i, e) in enumerate(exercises):
	aux[i % 3] += e
print(['chest', 'biceps', 'back'][aux.index(max(aux))])


import math
n = int(input())
s = []
biceps = 0
back = 0
chest = 0
a = [int(n) for n in input().split(' ')]
for i in range(math.ceil(n / 3)):
	s.append(a[i * 3:i * 3 + 3])
s[-1].append(0)
s[-1].append(0)
s[-1].append(0)
for i in range(len(s)):
	chest = chest + s[i][0]
	biceps += s[i][1]
	back += s[i][2]
if chest == max(biceps, chest, back):
	print('chest')
elif biceps == max(biceps, chest, back):
	print('biceps')
elif back == max(biceps, chest, back):
	print('back')


n = int(input())
l = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
for i in range(3):
	for j in range(i, n, 3):
		if i == 0:
			chest += l[j]
		if i == 1:
			biceps += l[j]
		if i == 2:
			back += l[j]
s = max(chest, back, biceps)
if s == chest:
	print('chest')
if s == back:
	print('back')
if s == biceps:
	print('biceps')


n = int(input())
l = [int(i) for i in input().split()]
a = [0, 0, 0]
for i in range(n):
	a[i % 3] += l[i]
m = max(a)
if m == a[0]:
	print('chest')
elif m == a[1]:
	print('biceps')
else:
	print('back')


n = int(input(''))
a = list(map(int, input().split(' ')))
r = [0, 0, 0]
for i in range(n):
	r[i % 3] += a[i]
m = max(r)
if m == r[0]:
	print('chest')
elif m == r[1]:
	print('biceps')
elif m == r[2]:
	print('back')


n = int(input())
c = 0
bi = 0
ba = 0
a = list(map(int, input().split()))
for i in range(0, n):
	if i % 3 == 0:
		c += a[i]
	elif i % 3 == 1:
		bi += a[i]
	else:
		ba += a[i]
maxi = max(c, bi, ba)
if maxi == c:
	print('chest')
elif maxi == bi:
	print('biceps')
else:
	print('back')


x = int(input())
l = list(map(int, input().split()))
if x == 1:
	print('chest')
elif x == 2:
	if l[0] > l[1]:
		print('chest')
	else:
		print('biceps')
else:
	c = 0
	bc = 0
	ba = 0
	for i in range(0, x, 3):
		c += l[i]
	for i in range(1, x, 3):
		bc += l[i]
	for i in range(2, x, 3):
		ba += l[i]
	if max(c, bc, ba) == c:
		print('chest')
	elif max(c, bc, ba) == bc:
		print('biceps')
	else:
		print('back')


n = int(input())
a = list(map(int, input().split()))
muscles = [0, 0, 0]
answer = ['chest', 'biceps', 'back']
for i in range(len(a)):
	if i % 3 == 0:
		muscles[0] += a[i]
	elif i % 3 == 1:
		muscles[1] += a[i]
	else:
		muscles[2] += a[i]
strongest = muscles.index(max(muscles))
print(answer[strongest])


import sys
(mod, MOD) = (1000000007, 998244353)

def get_array():
	return list(map(int, sys.stdin.readline().strip().split()))

def get_ints():
	return map(int, sys.stdin.readline().strip().split())

def input():
	return sys.stdin.readline().strip()
n = int(input())
Arr = get_array()
chest = 0
biceps = 0
back = 0
for i in range(n):
	if i % 3 == 0:
		chest += Arr[i]
	elif i % 3 == 1:
		biceps += Arr[i]
	else:
		back += Arr[i]
if chest == max([chest, biceps, back]):
	print('chest')
elif biceps == max([chest, biceps, back]):
	print('biceps')
else:
	print('back')


from sys import stdin
from collections import defaultdict as dd
n = int(stdin.readline().rstrip())
l = list(map(int, stdin.readline().split()))
d = dd(int)
for i in range(n):
	d[i % 3] += l[i]
m = max(d[0], d[1], d[2])
if m == d[0]:
	print('chest')
elif m == d[1]:
	print('biceps')
else:
	print('back')


def bodybuilder():
	exercises = int(input())
	routine = input().split()
	dic = {'Chest': 0, 'Biceps': 0, 'Back': 0}
	while len(routine) != 0:
		for i in dic:
			if len(routine) == 0:
				break
			dic[i] += int(routine[0])
			routine.pop(0)
	if dic['Chest'] > dic['Biceps'] and dic['Chest'] > dic['Back']:
		print('chest')
		return
	elif dic['Biceps'] > dic['Chest'] and dic['Biceps'] > dic['Back']:
		print('biceps')
		return
	else:
		print('back')
		return
bodybuilder()


a = int(input())
ar = list(map(int, input().split()))
biceps = sum(ar[1::3])
chest = sum(ar[0::3])
back = sum(ar[2::3])
if chest > back:
	if chest > biceps:
		print('chest')
	else:
		print('biceps')
elif back > biceps:
	print('back')
else:
	print('biceps')


u = ['chest', 'biceps', 'back']
n = int(input())
a = [0, 0, 0]
i2 = 0
for i in input().split():
	a[i2] += int(i)
	i2 = (i2 + 1) % 3
i2 = 0
m = 0
i3 = 0
for i in a:
	if i > m:
		i3 = i2
		m = i
	i2 += 1
print(u[i3])


n = int(input())
l = [int(x) for x in input().split()]
chest = 0
biceps = 0
back = 0
for i in range(n):
	if i % 3 == 0:
		chest += l[i]
	elif i % 3 == 1:
		biceps += l[i]
	elif i % 3 == 2:
		back += l[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


import sys
n = int(input())
a = list(map(int, sys.stdin.readline().split()))
exo = ['chest', 'biceps', 'back']
nb = [0, 0, 0]
for i in range(len(a)):
	nb[i % 3] += a[i]
am = max(nb)
print(exo[nb.index(am)])


n = int(input())
line = list(map(int, input().split()))
x = 0
y = 0
z = 0
for i in range(n):
	if i % 3 == 0:
		x = x + line[i]
	elif i % 3 == 1:
		y = y + line[i]
	else:
		z = z + line[i]
s = max(x, y, z)
if x == s:
	print('chest')
elif y == s:
	print('biceps')
else:
	print('back')


nb_exer = int(input())
to_do = [int(x) for x in input().split()]
done = [0, 0, 0]
for i in range(nb_exer):
	done[i % 3] += to_do[i]
print(['chest', 'biceps', 'back'][done.index(max(done))])


n = int(input())
x = list(map(int, input().split()))
chests = 0
biceps = 0
backs = 0
for e in range(0, n, 3):
	chests = chests + x[e]
for e1 in range(1, n, 3):
	biceps = biceps + x[e1]
for e2 in range(2, n, 3):
	backs = backs + x[e2]
if chests > backs and chests > biceps:
	print('chest')
elif biceps > backs and biceps > chests:
	print('biceps')
else:
	print('back')


x = int(input())
l = input().split()
a = [0, 0, 0]
for (i, y) in enumerate(l):
	y = int(y)
	if i % 3 == 0:
		a[0] += y
	elif i % 3 == 1:
		a[1] += y
	elif i % 3 == 2:
		a[2] += y
x = max(a)
if a[0] == x:
	print('chest')
elif a[1] == x:
	print('biceps')
elif a[2] == x:
	print('back')


import math
from collections import *
import sys
from functools import reduce

def get_ints():
	return map(int, input().strip().split())

def get_list():
	return list(get_ints())

def get_string():
	return list(input().strip().split())

def printxsp(*args):
	return print(*args, end='')

def printsp(*args):
	return print(*args, end=' ')
UGLYMOD = int(1000000000.0) + 7
SEXYMOD = 998244353
MAXN = int(100000.0)
n = int(input())
li = get_list()
d = defaultdict(lambda : 0)
name = ['chest', 'biceps', 'back']
for i in range(n):
	d[name[i % 3]] += li[i]
print(max(d.items(), key=lambda x: x[1])[0])


n = int(input())
a = []
a += map(int, input().split())
c = 0
bic = 0
bk = 0
for i in range(0, n, 3):
	c += a[i]
	if i + 1 < len(a):
		bic += a[i + 1]
	if i + 2 < len(a):
		bk += a[i + 2]
if max(c, bic, bk) == c:
	print('chest')
elif max(c, bic, bk) == bic:
	print('biceps')
else:
	print('back')


n = int(input())
lst = list(map(int, input().split()))
(chest, biceps, back) = (0, 0, 0)
for i in range(n):
	if i % 3 == 0:
		chest += lst[i]
	elif i % 3 == 1:
		biceps += lst[i]
	elif i % 3 == 2:
		back += lst[i]
x = max(chest, biceps, back)
if x == chest:
	print('chest')
elif x == biceps:
	print('biceps')
elif x == back:
	print('back')


n = int(input())
l = list(map(int, input().split(' ')))
chest = 0
biceps = 0
back = 0
for i in range(n):
	if i % 3 == 0:
		chest += l[i]
	elif i % 3 == 1:
		biceps += l[i]
	else:
		back += l[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > back and biceps > chest:
	print('biceps')
else:
	print('back')


n = int(input())
s = [int(x) for x in input().split()]
a = [0, 0, 0]
for i in range(n):
	if i % 3 == 0:
		a[0] += s[i]
	elif i % 3 == 1:
		a[1] += s[i]
	else:
		a[2] += s[i]
m = a.index(max(a))
if m == 0:
	print('chest')
elif m == 1:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
chest = back = biceps = 0
i = 0
while n:
	if n == 1:
		chest = chest + a[i]
		n = n - 1
		i = i + 1
	elif n == 2:
		chest = chest + a[i]
		biceps = biceps + a[i + 1]
		n = n - 2
		i = i + 2
	else:
		chest = chest + a[i]
		biceps = biceps + a[i + 1]
		back = back + a[i + 2]
		n = n - 3
		i = i + 3
if chest >= biceps and chest >= back:
	print('chest')
elif biceps >= chest and biceps >= back:
	print('biceps')
else:
	print('back')


n = int(input())
x = [0] * 3
a = list(map(int, input().split()))
for i in range(n):
	if i % 3 == 0:
		x[0] += a[i]
	elif i % 3 == 1:
		x[1] += a[i]
	else:
		x[2] += a[i]
y = x.index(max(x))
if y == 0:
	print('chest')
elif y == 1:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
c = 0
d = {'chest': 0, 'biceps': 0, 'back': 0}
for i in range(n):
	c += 1
	if c == 1:
		d['chest'] += a[i]
	elif c == 2:
		d['biceps'] += a[i]
	else:
		d['back'] += a[i]
	if c == 3:
		c = 0
m = max(d.values())
for (j, k) in d.items():
	if k == m:
		print(j)
		break


n = int(input())
X = [int(p) for p in input().split(' ')]
biceps = 0
chest = 0
back = 0
for i in range(0, n):
	if (i + 1) % 3 == 2:
		biceps += X[i]
	if (i + 1) % 3 == 0:
		back += X[i]
	if (i + 1) % 3 == 1:
		chest += X[i]
if max(chest, biceps, back) == chest:
	print('chest')
if max(chest, biceps, back) == biceps:
	print('biceps')
if max(chest, biceps, back) == back:
	print('back')


n = int(input())
l = list(map(int, input().split()))
c1 = 0
c2 = 0
c3 = 0
for i in range(n):
	if i % 3 == 0:
		c1 += l[i]
	elif i % 3 == 1:
		c2 += l[i]
	else:
		c3 += l[i]
a = max(c1, c2, c3)
if a == c1:
	print('chest')
elif a == c2:
	print('biceps')
else:
	print('back')


n = int(input())
arr = list(map(int, input().rstrip().split()))
c = 0
bi = 0
b = 0
for i in range(n):
	val = arr[i]
	if i % 3 == 0:
		c = c + val
	elif i % 3 == 1:
		bi = bi + val
	else:
		b = b + val
ans = ''
if c > bi and c > b:
	ans = 'chest'
if bi > c and bi > b:
	ans = 'biceps'
if b > bi and b > c:
	ans = 'back'
print(ans)


n = int(input())
a = list(map(int, input().split()))
s = [0] * 3
for i in range(3):
	s[i] = sum(a[i:n:3])
if max(s) == s[0]:
	print('chest')
elif max(s) == s[1]:
	print('biceps')
else:
	print('back')


n = int(input())
s = list(map(int, input().rstrip().split()))
c = 0
b = 0
m = 0
r = 0
q = 0
t = 0
for i in range(n):
	if r == 0:
		c = c + s[i]
		r = r + 1
	elif q == 0:
		b = b + s[i]
		q = q + 1
	elif t == 0:
		m = m + s[i]
		t = t + 1
	if r == 1 and q == 1 and (t == 1):
		r = 0
		q = 0
		t = 0
f = max(c, b, m)
if f == c:
	print('chest')
elif f == b:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
turn = ['chest', 'biceps', 'back'] * 20
for i in range(n):
	s = turn[i]
	if s == 'chest':
		chest += a[i]
	elif s == 'biceps':
		biceps += a[i]
	elif s == 'back':
		back += a[i]
if chest > biceps and chest > back:
	print('chest')
elif back > biceps and back > chest:
	print('back')
elif biceps > chest and biceps > back:
	print('biceps')


a = int(input())
b = list(map(int, input().split()))
c = 0
t0 = 0
t1 = 0
t2 = 0
mt = []
for i in b:
	if c == 0:
		t0 += i
	elif c == 1:
		t1 += i
	else:
		t2 += i
	c += 1
	if c == 3:
		c = 0
mt.append(t0)
mt.append(t1)
mt.append(t2)
for i in range(3):
	if mt[i] == max(mt) and i == 0:
		print('chest')
		break
	elif mt[i] == max(mt) and i == 1:
		print('biceps')
		break
	elif mt[i] == max(mt) and i == 2:
		print('back')
		break


import math
import sys
import string

def ri():
	return input()

def ii():
	return int(input())

def li():
	return input().split()

def mi():
	return list(map(int, input().split()))
n = ii()
a = mi()
c = [a[i] for i in range(0, n, 3)]
b = [a[i] for i in range(1, n, 3)]
back = [a[i] for i in range(2, n, 3)]
if sum(c) > sum(b) and sum(c) > sum(back):
	print('chest')
elif sum(b) > sum(c) and sum(b) > sum(back):
	print('biceps')
else:
	print('back')


x = int(input(''))
ar = list(map(int, input('').split()))
ch = bi = ba = 0
for i in range(len(ar)):
	j = i % 3
	if j == 0:
		ch = ch + ar[i]
	elif j == 1:
		bi = bi + ar[i]
	else:
		ba = ba + ar[i]
j = max(ch, bi, ba)
if j == ch:
	print('chest')
elif j == ba:
	print('back')
else:
	print('biceps')


n = int(input())
a = [int(i) for i in input().split()]
chest = 0
biceps = 0
back = 0
for i in range(0, len(a), 3):
	chest += a[i]
for i in range(1, len(a), 3):
	biceps += a[i]
for i in range(2, len(a), 3):
	back += a[i]
res = max(chest, biceps, back)
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
s1 = s2 = s3 = 0
for i in range(0, len(a), 3):
	s1 = s1 + a[i]
for j in range(1, len(a), 3):
	s2 = s2 + a[j]
for k in range(2, len(a), 3):
	s3 = s3 + a[k]
if max(s1, s2, s3) == s1:
	print('chest')
elif max(s1, s2, s3) == s2:
	print('biceps')
else:
	print('back')


a = int(input())
l = list(map(int, input().split()))
(x, y, z) = (0, 0, 0)
for i in range(1, a + 1):
	if i % 3 == 1:
		x += l[i - 1]
	elif i % 3 == 2:
		y += l[i - 1]
	else:
		z += l[i - 1]
p = max(x, y, z)
if p == x:
	print('chest')
elif p == y:
	print('biceps')
else:
	print('back')


n = int(input())
s = [int(i) for i in input().split()]
c = 0
b = 0
ba = 0
for i in range(0, n, 3):
	c += s[i]
for i in range(1, n, 3):
	b += s[i]
for i in range(2, n, 3):
	ba += s[i]
if c > b and c > ba:
	print('chest')
elif b > ba and b > c:
	print('biceps')
else:
	print('back')


N = int(input())
exercises = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
trible_counter = 1
for i in range(N):
	if trible_counter > 3:
		trible_counter = 1
	if trible_counter == 1:
		chest += exercises[i]
		trible_counter += 1
		continue
	if trible_counter == 2:
		biceps += exercises[i]
		trible_counter += 1
		continue
	if trible_counter == 3:
		back += exercises[i]
		trible_counter += 1
		continue
if chest > biceps and chest > back:
	print('chest')
if biceps > chest and biceps > back:
	print('biceps')
if back > biceps and back > chest:
	print('back')


import sys
input = sys.stdin.readline
n = int(input())
a = list(map(int, input().split()))
one = 0
two = 0
three = 0
for i in range(n):
	if i % 3 == 0:
		one += a[i]
	if i % 3 == 1:
		two += a[i]
	if i % 3 == 2:
		three += a[i]
if one == max(one, two, three):
	print('chest')
if two == max(one, two, three):
	print('biceps')
if three == max(one, two, three):
	print('back')


n = int(input())
exercises = list(input().split()[:n])
plan = []
for i in range(len(exercises)):
	exercises[i] = int(exercises[i])
for i in range(0, len(exercises), 3):
	plan.append(exercises[i:i + 3])
chest = 0
biceps = 0
back = 0
for x in plan:
	if len(x) < 3:
		y = 3 - len(x)
		for z in range(y):
			x.append(0)
	for i in range(len(x) - 2):
		chest += x[i]
		biceps += x[i + 1]
		back += x[i + 2]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
elif back > chest and back > biceps:
	print('back')


n = int(input())
l = list(map(int, input().split()))
a = []
for i in range(0, len(l), 3):
	a.append(l[i:i + 3])
c = 0
bi = 0
ba = 0
for x in range(len(a)):
	for y in range(len(a[x])):
		if y == 0:
			c = c + a[x][y]
		elif y == 1:
			bi = bi + a[x][y]
		elif y == 2:
			ba = ba + a[x][y]
if c > bi and c > ba:
	print('chest')
elif bi > c and bi > ba:
	print('biceps')
else:
	print('back')


n = int(input())
ls = [int(i) for i in input().split()]
chest = 0
biceps = 0
back = 0
for i in range(0, len(ls)):
	if i % 3 == 0:
		chest += ls[i]
	elif i % 3 == 1:
		biceps += ls[i]
	else:
		back += ls[i]
maxval = max(chest, biceps, back)
if maxval == chest:
	print('chest')
elif maxval == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
s = [int(i) for i in input().split()]
s1 = s2 = s3 = 0
for i in range(1, n + 1):
	if i % 3 == 1:
		s1 += s[i - 1]
	if i % 3 == 2:
		s2 += s[i - 1]
	if i % 3 == 0:
		s3 += s[i - 1]
macks = max(s1, s2, s3)
if macks == s1:
	print('chest')
elif macks == s2:
	print('biceps')
elif macks == s3:
	print('back')


def strongest_muscle(repeats):
	muscles = {}
	muscles['chest'] = 0
	muscles['biceps'] = 0
	muscles['back'] = 0
	for i in range(len(repeats)):
		if i % 3 == 0:
			muscles['chest'] += repeats[i]
		elif i % 3 == 1:
			muscles['biceps'] += repeats[i]
		else:
			muscles['back'] += repeats[i]
	return max(muscles, key=lambda k: muscles[k])
n = int(input())
print(strongest_muscle(list(map(int, input().split()))))


a = int(input())
b = list(map(int, input().split()))
ch = 0
bi = 0
ba = 0
for i in range(len(b)):
	if i < 3:
		if i == 0:
			ch += b[i]
		if i == 1:
			bi += b[i]
		if i == 2:
			ba += b[i]
	else:
		if i % 3 == 0:
			ch += b[i]
		if i % 3 == 1:
			bi += b[i]
		if i % 3 == 2:
			ba += b[i]
if ch > bi and ch > ba:
	print('chest')
elif ch < bi and bi > ba:
	print('biceps')
elif ba > ch and ba > bi:
	print('back')


n = int(input())
q = [0] * 4
inp = [int(x) for x in input().split()]
it = 1
for x in inp:
	q[it] += x
	it += 1
	if it == 4:
		it = 1
temp = q.index(max(q))
if temp == 1:
	print('chest')
elif temp == 2:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
a = [0, 0, 0]
for i in range(n):
	t = i % 3
	a[t] += l[i]
_max = max(a)
if a[0] == _max:
	print('chest')
elif a[1] == _max:
	print('biceps')
else:
	print('back')


c = 0
bi = 0
ba = 0
n = int(input())
m = list(map(int, input().split()))
x = 1
for i in m:
	if x == 1:
		c += i
	elif x == 2:
		bi += i
	elif x == 3:
		ba += i
		x = 0
	x += 1
if c > ba and c > bi:
	print('chest')
elif ba > c and ba > bi:
	print('back')
elif bi > c and bi > ba:
	print('biceps')


n = int(input())
ex = list(map(int, input().split()))
musc = ['chest', 'biceps', 'back']
num_total = [sum([ex[i] for i in range(n) if i % 3 == 0]), sum([ex[i] for i in range(n) if i % 3 == 1]), sum([ex[i] for i in range(n) if i % 3 == 2])]
print(musc[num_total.index(max(num_total))])


MAP_TYPES = {0: 'chest', 1: 'biceps', 2: 'back'}

def maxTypeExcersice(a):
	total = len(MAP_TYPES.keys())
	table = [0] * total
	for (i, value) in enumerate(a):
		table[i % total] += value
	return MAP_TYPES[table.index(max(table))]
n = int(input())
a = [int(i) for i in input().split()]
print(maxTypeExcersice(a))


n = int(input())
arr = list(map(int, input().split()))
(c, bi, bc) = (0, 0, 0)
for i in range(n):
	if i % 3 == 0:
		c += arr[i]
	elif i % 3 == 1:
		bi += arr[i]
	else:
		bc += arr[i]
if max(c, bi, bc) == c:
	print('chest')
elif max(c, bi, bc) == bi:
	print('biceps')
else:
	print('back')


input()
A = list(map(int, input().split()))
(chest_reps, biceps_reps, back_reps) = (sum(A[::3]), sum(A[1::3]), sum(A[2::3]))
if chest_reps > biceps_reps:
	print('chest' if chest_reps > back_reps else 'back')
else:
	print('biceps' if biceps_reps > back_reps else 'back')


from sys import stdin

def main():
	stdin.readline()
	l = [0, 0, 0]
	for (i, a) in enumerate(map(int, stdin.readline().strip().split())):
		l[i % 3] += a
	return ('chest', 'biceps', 'back')[max(0, 1, 2, key=l.__getitem__)]
print(main())


n = int(input())
x = list(map(int, input().split()))
chest = []
biceps = []
back = []
for i in range(n):
	if i % 3 == 0:
		chest.append(x[i])
	elif i % 3 == 1:
		biceps.append(x[i])
	else:
		back.append(x[i])
chest = sum([0] + chest)
biceps = sum([0] + biceps)
back = sum([0] + back)
answer = max(chest, biceps, back)
if answer == chest:
	print('chest')
elif answer == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
i = 0
j = 1
k = 2
c = bcp = b = 0
while i < n or j < n or k < n:
	if i < n:
		c += a[i]
		i += 3
	if j < n:
		bcp += a[j]
		j += 3
	if k < n:
		b += a[k]
		k += 3
if c > bcp and c > b:
	print('chest')
elif bcp > c and bcp > b:
	print('biceps')
elif b > c and b > bcp:
	print('back')


n = int(input())
a = [int(x) for x in input().split()]
x = 0
y = 0
z = 0
if n >= 3:
	for i in range(0, n, 3):
		x += a[i]
	for i in range(1, n, 3):
		y += a[i]
	for i in range(2, n, 3):
		z += a[i]
	ans = max(x, y, z)
	if ans == x:
		print('chest')
	elif ans == y:
		print('biceps')
	elif ans == z:
		print('back')
elif n == 2:
	ans = max(a)
	if ans == a[0]:
		print('chest')
	elif ans == a[1]:
		print('biceps')
else:
	print('chest')


n = int(input())
ans = [0, 0, 0]
t = []
t += map(int, input().split())
for i in range(n):
	ans[i % 3] += t[i]
if ans[0] > ans[1] and ans[0] > ans[2]:
	print('chest')
elif ans[1] > ans[2]:
	print('biceps')
else:
	print('back')


a = int(input())
l = list(map(int, input().split()))
ch = 0
bic = 0
bac = 0
count = 1
for i in range(a):
	if count % 3 == 0:
		bac += l[i]
	elif count % 2 == 0:
		bic += l[i]
	else:
		ch += l[i]
	count += 1
	if count == 4:
		count = 1
e = max([bac, bic, ch])
if e == bac:
	print('back')
elif e == bic:
	print('biceps')
else:
	print('chest')


x = int(input())
l = [int(n) for n in input().split()]
res = [0, 0, 0]
i = 0
while i < len(l):
	res[0] += l[i]
	if i + 1 < len(l):
		res[1] += l[i + 1]
	if i + 2 < len(l):
		res[2] += l[i + 2]
	i = i + 3
rI = res.index(max(res))
if rI == 0:
	print('chest')
if rI == 1:
	print('biceps')
if rI == 2:
	print('back')


n = int(input())
b = list(map(int, input().split()))
j = 1
ch = 0
bi = 0
ba = 0
for i in range(n):
	if j % 3 == 1:
		ch = ch + b[i]
	if j % 3 == 2:
		bi = bi + b[i]
	if j % 3 == 0:
		ba = ba + b[i]
	j = j + 1
if ba > bi and ba > ch:
	print('back')
if bi > ba and bi > ch:
	print('biceps')
if ch > ba and ch > bi:
	print('chest')


n = int(input())
c = list(map(int, input().split()))
b = ['chest', 'biceps', 'back']
a = [0] * 3
for i in range(n):
	a[i % 3] += c[i]
print(b[a.index(max(a))])


(n, l) = (int(input()), [0] * 3)
a = list(map(int, input().split()))
for i in range(n):
	l[i % 3] += a[i]
print('cbbhiaeccsektp  s '[l.index(max(l))::3])


n = int(input())
l = list(map(int, input().split()))
(s1, s2, s3) = (0, 0, 0)
for i in range(0, n, 3):
	s1 += l[i]
for i in range(1, n, 3):
	s2 += l[i]
for i in range(2, n, 3):
	s3 += l[i]
if s1 > s2 and s1 > s3:
	print('chest')
elif s2 > s3 and s2 > s1:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
t = [0, 0, 0]
for x in range(n):
	t[x % 3] += a[x]
maximum = t.index(max(t))
if maximum == 0:
	print('chest')
elif maximum == 1:
	print('biceps')
else:
	print('back')


input()
arr = [int(i) for i in input().split()]
a = sum(arr[::3])
b = sum(arr[1::3])
c = sum(arr[2::3])
(_, ans) = max((a, 'chest'), (b, 'biceps'), (c, 'back'))
print(ans)


input()
k = list(map(int, input().split()))
c = {sum(k[::3]): 'chest', sum(k[1::3]): 'biceps', sum(k[2::3]): 'back'}
print(c.get(max(c)))


q = lambda : map(int, input().split())
qi = lambda : int(input())
qs = lambda : input().split()
n = qi()
a = list(q())
x = [sum((a[i] for i in range(0, n, 3))), sum((a[i] for i in range(1, n, 3))), sum((a[i] for i in range(2, n, 3)))]
print(['chest', 'biceps', 'back'][x.index(max(x))])


n = int(input())
a = list(map(int, input().split()))
chest = []
biceps = []
back = []
for i in range(n):
	if i % 3 == 0:
		chest.append(a[i])
	if i % 3 == 1:
		biceps.append(a[i])
	if i % 3 == 2:
		back.append(a[i])
if sum(back) > sum(chest) and sum(back) > sum(biceps):
	print('back')
elif sum(chest) > sum(back) and sum(chest) > sum(biceps):
	print('chest')
elif sum(biceps) > sum(chest) and sum(biceps) > sum(back):
	print('biceps')


import os
import sys
from io import BytesIO, IOBase
import math as M
import itertools as ITR
from collections import defaultdict as D
from collections import Counter as C
from collections import deque as Q
import threading
from functools import lru_cache, reduce
from functools import cmp_to_key as CMP
from bisect import bisect_left as BL
from bisect import bisect_right as BR
import random as R
import string
import cmath, time
enum = enumerate
start_time = time.time()
MOD = 1000000007
MA = float('inf')
MI = float('-inf')
di8 = ((1, 0), (1, 1), (0, 1), (-1, 1), (-1, 0), (-1, -1), (0, -1), (1, -1))
di4 = ((1, 0), (0, 1), (-1, 0), (0, -1))

def increase_stack():
	sys.setrecursionlimit(2 ** 32 // 2 - 1)
	threading.stack_size(1 << 27)

def binary(n):
	return bin(n)[2:]

def decimal(s):
	return int(s, 2)

def pow2(n):
	p = 0
	while n > 1:
		n //= 2
		p += 1
	return p

def maxfactor(n):
	q = []
	for i in range(1, int(n ** 0.5) + 1):
		if n % i == 0:
			q.append(i)
	if q:
		return q[-1]

def factors(n):
	q = []
	for i in range(1, int(n ** 0.5) + 1):
		if n % i == 0:
			q.append(i)
			q.append(n // i)
	return list(sorted(list(set(q))))

def primeFactors(n):
	l = []
	while n % 2 == 0:
		l.append(2)
		n = n / 2
	for i in range(3, int(M.sqrt(n)) + 1, 2):
		while n % i == 0:
			l.append(i)
			n = n / i
	if n > 2:
		l.append(int(n))
	l.sort()
	return l

def isPrime(n):
	if n == 1:
		return False
	else:
		root = int(n ** 0.5)
		root += 1
		for i in range(2, root):
			if n % i == 0:
				return False
		return True

def seive(n):
	a = []
	prime = [True for i in range(n + 1)]
	p = 2
	while p * p <= n:
		if prime[p] == True:
			for i in range(p ** 2, n + 1, p):
				prime[i] = False
		p = p + 1
	for p in range(2, n + 1):
		if prime[p]:
			a.append(p)
	prime[0] = prime[1] = False
	return (a, prime)

def maxPrimeFactors(n):
	maxPrime = -1
	while n % 2 == 0:
		maxPrime = 2
		n >>= 1
	for i in range(3, int(M.sqrt(n)) + 1, 2):
		while n % i == 0:
			maxPrime = i
			n = n / i
	if n > 2:
		maxPrime = n
	return int(maxPrime)

def countchar(s, i):
	c = 0
	ch = s[i]
	for i in range(i, len(s)):
		if s[i] == ch:
			c += 1
		else:
			break
	return c

def str_counter(a):
	q = [0] * 26
	for i in range(len(a)):
		q[ord(a[i]) - 97] = q[ord(a[i]) - 97] + 1
	return q

def lis(arr):
	n = len(arr)
	lis = [1] * n
	maximum = 0
	for i in range(1, n):
		for j in range(0, i):
			if arr[i] > arr[j] and lis[i] < lis[j] + 1:
				lis[i] = lis[j] + 1
				maximum = max(maximum, lis[i])
	return maximum

def lcm(arr):
	a = arr[0]
	val = arr[0]
	for i in range(1, len(arr)):
		gcd = gcd(a, arr[i])
		a = arr[i]
		val *= arr[i]
	return val // gcd

def ncr(n, r):
	return M.factorial(n) // (M.factorial(n - r) * M.factorial(r))

def npr(n, r):
	return M.factorial(n) // M.factorial(n - r)

def IF(c, t, f):
	return t if c else f

def YES(c):
	print(IF(c, 'YES', 'NO'))

def Yes(c):
	print(IF(c, 'Yes', 'No'))

def yes(c):
	print(IF(c, 'yes', 'no'))

def JA(a, sep=' '):
	print(sep.join(map(str, a)))

def JAA(a, s='\n', t=' '):
	return s.join((t.join(map(str, b)) for b in a))

def PS(a, s=' '):
	print(str(a), end=s)

def I():
	return int(inp())

def F():
	return float(inp())

def LI():
	return list(map(int, inp().split()))

def LF():
	return list(map(float, inp().split()))

def MATI(n):
	return [LI() for i in range(n)]

def MATS(n):
	return [list(inp()) for i in range(n)]

def IV():
	return map(int, inp().split())

def FV():
	return map(float, inp().split())

def LS():
	return list(inp())

def S():
	return inp()
BUFSIZE = 8192

class FastIO(IOBase):
	newlines = 0

	def __init__(self, file):
		self._fd = file.fileno()
		self.buffer = BytesIO()
		self.writable = 'x' in file.mode or 'r' not in file.mode
		self.write = self.buffer.write if self.writable else None

	def read(self):
		while True:
			b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
			if not b:
				break
			ptr = self.buffer.tell()
			(self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr))
		self.newlines = 0
		return self.buffer.read()

	def readline(self):
		while self.newlines == 0:
			b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
			self.newlines = b.count(b'\n') + (not b)
			ptr = self.buffer.tell()
			(self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr))
		self.newlines -= 1
		return self.buffer.readline()

	def flush(self):
		if self.writable:
			os.write(self._fd, self.buffer.getvalue())
			(self.buffer.truncate(0), self.buffer.seek(0))

class IOWrapper(IOBase):

	def __init__(self, file):
		self.buffer = FastIO(file)
		self.flush = self.buffer.flush
		self.writable = self.buffer.writable
		self.write = lambda s: self.buffer.write(s.encode('ascii'))
		self.read = lambda : self.buffer.read().decode('ascii')
		self.readline = lambda : self.buffer.readline().decode('ascii')
(sys.stdin, sys.stdout) = (IOWrapper(sys.stdin), IOWrapper(sys.stdout))
inp = lambda : sys.stdin.readline().rstrip('\r\n')
TestCases = 0

def solve():
	n = I()
	arr = LI()
	cou = [0, 0, 0]
	for (i, ele) in enum(arr):
		cou[i % 3] += ele
	ma = MI
	ind = -1
	for (i, ele) in enum(cou):
		if ma < ele:
			ma = ele
			ind = i
	res = ['chest', 'biceps', 'back']
	print(res[ind])

def main():
	flag = 1
	try:
		sys.stdin = open('c:/Users/Manoj Chowdary/Documents/python/CodeForces/contest-div-2/input.txt', 'r')
		sys.stdout = open('c:/Users/Manoj Chowdary/Documents/python/CodeForces/contest-div-2/output.txt', 'w')
	except:
		flag = 0
	t = 1
	if TestCases:
		t = I()
	for _ in range(1, t + 1):
		solve()
	if flag:
		print('Time: %.4f sec' % (time.time() - start_time))
		localtime = time.asctime(time.localtime(time.time()))
		print(localtime)
		sys.stdout.close()
main()


input()
l = [int(x) for x in input().split()]
a = sum(l[0::3])
b = sum(l[1::3])
c = sum(l[2::3])
if a > b and a > c:
	print('chest')
elif b > a and b > c:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
x = y = z = 0
t = n % 3
for i in range(0, n - t, 3):
	x += l[i]
	y += l[i + 1]
	z += l[i + 2]
if t == 1:
	x += l[n - 1]
elif t == 2:
	x += l[n - 2]
	y += l[n - 1]
if x >= y and x >= z:
	print('chest')
elif y >= x and y >= z:
	print('biceps')
else:
	print('back')


n = int(input())
li = list(map(int, input().split()))
(c, b, d) = (0, 0, 0)
for i in range(len(li)):
	if i % 3 == 0:
		c += li[i]
	elif i % 3 == 1:
		b += li[i]
	elif i % 3 == 2:
		d += li[i]
if c > b and c > d:
	print('chest')
elif b > c and b > d:
	print('biceps')
else:
	print('back')


a = int(input())
b = input().split()
c = 0
bi = 0
bk = 0
for i in range(len(b)):
	if i % 3 == 0:
		c = c + int(b[i])
	elif i % 3 == 1:
		bi = bi + int(b[i])
	elif i % 3 == 2:
		bk = bk + int(b[i])
l = []
l.append(c)
l.append(bi)
l.append(bk)
d = max(l)
if l.index(d) == 0:
	print('chest')
elif l.index(d) == 1:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
c = sum(l[0:n:3])
bi = sum(l[1:n:3])
ba = sum(l[2:n:3])
if max(c, bi, ba) == c:
	print('chest')
elif max(c, bi, ba) == bi:
	print('biceps')
else:
	print('back')


input()
ar = list(map(int, input().split()))
cur = 0
(ch, bi, ba) = (0, 0, 0)
for a in ar:
	if cur % 3 == 0:
		ch += a
	elif cur % 3 == 1:
		bi += a
	else:
		ba += a
	cur += 1
if ch == max([ch, bi, ba]):
	print('chest')
elif bi == max([ch, bi, ba]):
	print('biceps')
else:
	print('back')


def main():
	n = int(input())
	a = list(map(int, input().split()))
	chest = biceps = back = 0
	for i in range(n):
		if (i + 1) % 3 == 0:
			back += a[i]
		elif (i + 1) % 3 == 2:
			biceps += a[i]
		else:
			chest += a[i]
	if back > biceps and back > chest:
		print('back')
	elif biceps > chest:
		print('biceps')
	else:
		print('chest')
main()


n = int(input())
a = list(map(int, input().split()))
counta = 0
countb = 0
countc = 0
for i in range(0, n, 3):
	counta += a[i]
for i in range(1, n, 3):
	countb += a[i]
for i in range(2, n, 3):
	countc += a[i]
ans = max(counta, countb, countc)
if ans == counta:
	print('chest')
elif ans == countb:
	print('biceps')
elif ans == countc:
	print('back')


A = input()
B = input().split()
B = list(map(int, B))
chest = B[::3]
biceps = B[1::3]
back = B[2::3]
chest = sum(chest)
biceps = sum(biceps)
back = sum(back)
max = max(chest, biceps, back)
if chest == max:
	print('chest')
elif biceps == max:
	print('biceps')
else:
	print('back')


n = input()
n = int(n)
sets = list(map(int, input().split(' ')))
muscles = {'chest': 0, 'biceps': 0, 'back': 0}
for i in range(0, n):
	if i % 3 == 2:
		muscles['back'] += sets[i]
	elif i % 3 == 1:
		muscles['biceps'] += sets[i]
	else:
		muscles['chest'] += sets[i]
for key in muscles.keys():
	if muscles[key] == max(muscles.values()):
		print(key)


n = int(input())
n_a = list(map(int, input().split()))
count = 1
(chest, biceps, back) = (0, 0, 0)
for i in range(len(n_a)):
	if count == 1:
		chest += n_a[i]
		count += 1
	elif count == 2:
		biceps += n_a[i]
		count += 1
	elif count == 3:
		back += n_a[i]
		count = 1
if chest >= biceps >= back or chest >= back >= biceps:
	print('chest')
elif biceps >= back >= chest or biceps >= chest >= back:
	print('biceps')
elif back >= chest >= biceps or back >= biceps >= chest:
	print('back')


chest = 0
biceps = 0
back = 0
n = int(input())
z = list(map(int, input().split()))
third = 3
second = 2
for i in range(n):
	if i + 1 == third:
		back += z[i]
		third += 3
	elif i + 1 == second:
		biceps += z[i]
		second += 3
	else:
		chest += z[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


(n, t) = (int(input()), list(map(int, input().split())))
(p, t) = ([0] * 3, t + [0] * (3 - n % 3))
for i in range(0, n, 3):
	for j in range(3):
		p[j] += t[i + j]
print(['chest', 'biceps', 'back'][p.index(max(p))])


def main() -> int:
	n = int(input())
	exercises = [int(word) for word in input().split()]
	total = [0] * 3
	for i in range(3):
		total[i] = sum(exercises[i::3])
	max_index = total.index(max(total))
	exercise_names = ['chest', 'biceps', 'back']
	print(exercise_names[max_index])
	return 0

def __starting_point():
	main()
__starting_point()


from sys import stdin, stdout
n = int(stdin.readline().strip())
ex_count = list(map(int, stdin.readline().split()))
ex_lst = [0, 0, 0]
ex_dict = {0: 'chest', 1: 'biceps', 2: 'back'}
for i in range(n):
	index = i % 3
	ex_lst[index] += ex_count[i]
max_ex = ex_lst.index(max(ex_lst))
stdout.write(ex_dict[max_ex])


n = int(input())
arr = list(map(int, input().split()))
(chest, biceps, back) = (0, 0, 0)
for i in range(0, n, 3):
	chest += arr[i]
for i in range(1, n, 3):
	biceps += arr[i]
for i in range(2, n, 3):
	back += arr[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
elif back > chest and back > biceps:
	print('back')


R = lambda : map(int, input().split())
n = int(input())
a = list(R())
ans = [0, 0, 0]
x = 0
for i in a:
	ans[x] += i
	x += 1
	if x > 2:
		x = 0
m = max(ans)
if m == ans[0]:
	print('chest')
elif m == ans[1]:
	print('biceps')
else:
	print('back')


n = int(input())
l = [*map(int, input().split())]
a = [0, 0, 0]
a[0] = sum(l[::3])
a[1] = sum(l[1::3])
a[2] = sum(l[2::3])
ind = a.index(max(a))
if ind == 0:
	print('chest')
elif ind == 1:
	print('biceps')
else:
	print('back')


def s(p):
	r = 0
	for i in range(len(p)):
		r += p[i]
	return r
n = int(input())
r = input()
l = list(r.split())
x = []
y = []
z = []
for i in range(len(l)):
	if i % 3 == 0:
		l[i] = int(l[i])
		y.append(l[i])
	elif i % 3 == 1:
		l[i] = int(l[i])
		z.append(l[i])
	else:
		l[i] = int(l[i])
		x.append(l[i])
if s(x) > s(y) and s(x) > s(z):
	print('back')
if s(y) > s(x) and s(y) > s(z):
	print('chest')
if s(z) > s(y) and s(z) > s(x):
	print('biceps')


n = int(input())
s = list(map(int, input().split()))
a = sum(s[0:n:3])
b = sum(s[1:n:3])
c = sum(s[2:n:3])
d = max(a, b, c)
if a == d:
	print('chest')
elif b == d:
	print('biceps')
else:
	print('back')


n = int(input())
(x, y, z) = (0, 0, 0)
l = list(map(int, input().split()))
x = sum(l[0:len(l):3])
y = sum(l[1:len(l):3])
z = sum(l[2:len(l):3])
if x == max(x, y, z):
	print('chest')
elif y == max(x, y, z):
	print('biceps')
elif z == max(x, y, z):
	print('back')


class CodeforcesTask255ASolution:

	def __init__(self):
		self.result = ''
		self.n = 0
		self.tasks = []

	def read_input(self):
		self.n = int(input())
		self.tasks = [int(x) for x in input().split(' ')]

	def process_task(self):
		res = [0] * 3
		for x in range(self.n):
			res[x % 3] += self.tasks[x]
		self.result = ['chest', 'biceps', 'back'][res.index(max(res))]

	def get_result(self):
		return self.result
Solution = CodeforcesTask255ASolution()
Solution.read_input()
Solution.process_task()
print(Solution.get_result())


import operator
n = int(input())
a = list(map(int, input().split()))
c = []
x = ['chest', 'biceps', 'back']
for i in range(3):
	c.append(sum(a[i::3]))
mapped = zip(x, c)
print(sorted(list(mapped), key=operator.itemgetter(1))[-1][0])


n = int(input())
x = list(map(int, input().split()))
n = len(x)
for i in range(n):
	a = sum(x[::3])
	b = sum(x[1::3])
	c = sum(x[2::3])
if a > b and a > c:
	print('chest')
elif b > a and b > c:
	print('biceps')
elif c > a and c > b:
	print('back')


n = int(input())
a = list(map(int, input().split()))
p = 0
q = 0
r = 0
for i in range(0, n, 3):
	p = p + a[i]
for i in range(1, n, 3):
	q = q + a[i]
for j in range(2, n, 3):
	r = r + a[j]
if p > q and p > r:
	print('chest')
elif q > p and q > r:
	print('biceps')
elif r > q and r > p:
	print('back')


n = int(input())
mas = list(map(int, input().split(' ')))
t1 = sum(mas[0::3])
t2 = sum(mas[1::3])
t3 = sum(mas[2::3])
if t1 > t2 and t1 > t3:
	print('chest')
elif t2 > t1 and t2 > t3:
	print('biceps')
elif t3 > t1 and t3 > t2:
	print('back')


n = int(input())
t = list(map(int, input().split()))
chest = sum(t[::3])
biceps = sum(t[1::3])
back = sum(t[2::3])
if biceps < chest > back:
	print('chest')
elif chest < biceps > back:
	print('biceps')
elif chest < back > biceps:
	print('back')


int(input())
a = [int(x) for x in input().split()]
b = [sum(a[::3]), sum(a[1::3]), sum(a[2::3])]
c = ['chest', 'biceps', 'back']
print(c[b.index(max(b))])


n = int(input())
masses = input().split()
muscle = ['chest', 'biceps', 'back']
i = 0
res = [0] * 3
for mass in masses:
	res[i % 3] += int(mass)
	i += 1
print(muscle[res.index(max(res))])


n = int(input())
s = input()
l = s.split()
l = [int(i) for i in l]
c = []
b = []
ba = []
for i in l[::3]:
	c.append(i)
for i in l[1::3]:
	b.append(i)
for i in l[2::3]:
	ba.append(i)
if sum(c) > sum(b) and sum(c) > sum(ba):
	print('chest')
elif sum(b) > sum(c) and sum(b) > sum(ba):
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
(y1, y2, y3) = (0, 0, 0)
for i in range(len(a)):
	if i % 3 == 0:
		y1 += a[i]
	elif i % 3 == 1:
		y2 += a[i]
	else:
		y3 += a[i]
if y1 > y2 and y1 > y3:
	print('chest')
elif y2 > y1 and y2 > y3:
	print('biceps')
else:
	print('back')


n = int(input())
arr = list(map(int, input().split(' ')))
if len(arr) < 3:
	if len(arr) == 1:
		print('chest')
	if len(arr) == 2:
		if max(arr) == arr[0]:
			print('chest')
			exit(0)
		else:
			print('biceps')
			exit(0)
elif len(arr) % 3 == 0:
	l = []
	i = 0
	while i < len(arr):
		l.append(arr[i:i + 3])
		i += 3
	for j in range(1, len(l)):
		l[0][0] += l[j][0]
		l[0][1] += l[j][1]
		l[0][2] += l[j][2]
	if max(l[0]) == l[0][0]:
		print('chest')
		exit(0)
	if max(l[0]) == l[0][1]:
		print('biceps')
		exit(0)
	if max(l[0]) == l[0][2]:
		print('back')
		exit(0)
else:
	a = []
	k = 0
	while k < len(arr):
		t = arr[k:k + 3]
		if len(t) == 2:
			t.append(0)
		if len(t) == 1:
			t.append(0)
			t.append(0)
		a.append(t)
		k += 3
	for I in range(1, len(a)):
		a[0][0] += a[I][0]
		a[0][1] += a[I][1]
		a[0][2] += a[I][2]
	if max(a[0]) == a[0][0]:
		print('chest')
		exit(0)
	if max(a[0]) == a[0][1]:
		print('biceps')
		exit(0)
	if max(a[0]) == a[0][2]:
		print('back')
		exit(0)


n = int(input())
l = list(map(int, input().split()))
a = 0
b = 0
c = 0
i = 0
while i < n:
	a = a + l[i]
	if i + 1 >= n:
		break
	b = b + l[i + 1]
	if i + 2 >= n:
		break
	c = c + l[i + 2]
	i = i + 3
if max(a, b, c) == a:
	print('chest')
elif max(a, b, c) == b:
	print('biceps')
else:
	print('back')


def ii():
	return int(input())

def mi():
	return map(int, input().split())

def si():
	return [int(x) for x in input().split()]

def ss():
	return [x for x in input()]
a = ii()
s = si()
b = []
for i in range(3):
	b.append(sum(s[i::3]))
if b[0] == max(b):
	print('chest')
elif b[1] == max(b):
	print('biceps')
else:
	print('back')


count = int(input())
muscles = ['chest', 'biceps', 'back']
training = [int(i) for i in input().split(' ')]
sums = [0, 0, 0]
for i in range(len(training)):
	sums[i % 3] += training[i]
maxIndex = sums.index(max(sums))
print(muscles[maxIndex])


n = int(input())
count = 0
ar = list(map(int, input().split()))
count += sum(ar[0::3])
count1 = 0
count2 = 0
count1 = sum(ar[1::3])
count2 = sum(ar[2::3])
t = max(count, count1, count2)
if t == count:
	print('chest')
elif t == count1:
	print('biceps')
else:
	print('back')


n = int(input())
arr = list(map(int, input().split(' ')))
chest = 0
bicep = 0
back = 0
for x in range(n):
	if x % 3 == 0:
		chest += arr[x]
	elif x % 3 == 1:
		bicep += arr[x]
	else:
		back += arr[x]
if chest == max(chest, bicep, back):
	print('chest')
elif bicep == max(chest, bicep, back):
	print('biceps')
else:
	print('back')


n = int(input())
a = 0
b = 0
c = 0
s = 1
list1 = list(map(int, input().split()))
for i in range(n):
	if s == 1:
		a += list1[i]
	elif s == 2:
		b += list1[i]
	else:
		c += list1[i]
	s += 1
	if s > 3:
		s = 1
if a > b and a > c:
	print('chest')
elif b > a and b > c:
	print('biceps')
else:
	print('back')


n = int(input())
res = [0, 0, 0]
for (i, el) in enumerate(map(int, input().split())):
	res[i % 3] += el
if res[0] == max(res):
	print('chest')
elif res[1] == max(res):
	print('biceps')
else:
	print('back')


a = int(input())
c = 0
bi = 0
ba = 0
q = 1
w = 0
e = 0
s = list(map(int, input().split()))
for i in s:
	if q == 1:
		c += i
		q = 0
		w = 1
		continue
	if w == 1:
		bi += i
		w = 0
		e = 1
		continue
	if e == 1:
		ba += i
		e = 0
		q = 1
		continue
if bi > ba and bi > c:
	print('biceps')
elif ba > bi and ba > c:
	print('back')
else:
	print('chest')


num = int(input())
list = [int(x) for x in input().split(' ')]
dic = {'chest': 0, 'biceps': 0, 'back': 0}
for i in range(num):
	if i % 3 == 0:
		dic['chest'] += list[i]
	elif i % 3 == 1:
		dic['biceps'] += list[i]
	else:
		dic['back'] += list[i]
print(max(dic, key=dic.get))


N = int(input())
exercises = list(map(int, input().split()))
answers = ['chest', 'biceps', 'back']
max_times = [0] * 3
trible_counter = 1
for i in range(N):
	if trible_counter > 3:
		trible_counter = 1
	if trible_counter == 1:
		max_times[0] += exercises[i]
		trible_counter += 1
		continue
	if trible_counter == 2:
		max_times[1] += exercises[i]
		trible_counter += 1
		continue
	if trible_counter == 3:
		max_times[2] += exercises[i]
		trible_counter += 1
		continue
print(answers[max_times.index(max(max_times))])


input()
q = list(map(int, input().split()))
count = len(q)
q += [0, 0]
chest = 0
biceps = 0
back = 0
for i in range(0, count, 3):
	chest += q[i]
	biceps += q[i + 1]
	back += q[i + 2]
newdict = {chest: 'chest', biceps: 'biceps', back: 'back'}
print(newdict[max(newdict)])


def main():
	m = int(input())
	vals = [int(v) for v in input().split()]
	biceps = 'biceps'
	back = 'back'
	chest = 'chest'
	freq = {biceps: 0, back: 0, chest: 0}
	for (i, v) in enumerate(vals):
		if i % 3 == 0:
			freq[chest] += v
		elif i % 3 == 1:
			freq[biceps] += v
		elif i % 3 == 2:
			freq[back] += v
	res = sorted(freq.items(), key=lambda b: b[1], reverse=True)
	print(res[0][0])
main()


def int_lst_input():
	return [int(val) for val in input().split(' ')]

def int_input():
	return int(input())

def solve():
	n = int_input()
	a = int_lst_input()
	(ch, bi, ba) = (0, 0, 0)
	for i in range(0, n):
		if i % 3 == 0:
			ch += a[i]
		elif i % 3 == 1:
			bi += a[i]
		elif i % 3 == 2:
			ba += a[i]
	if ch > bi and ch > ba:
		print('chest')
	elif bi > ch and bi > ba:
		print('biceps')
	elif ba > ch and ba > bi:
		print('back')
solve()


input()
a = [*map(int, input().split())]
print(['chest', 'biceps', 'back'][max(0, 1, 2, key=lambda i: sum(a[i::3]))])


sa = input()
sa2 = input().split(' ')
sa3 = [int(x) for x in sa2]
chest = 0
biceps = 0
back = 0
for x in range(len(sa3)):
	if (x + 1) % 3 == 1:
		chest += sa3[x]
	elif (x + 1) % 3 == 2:
		biceps += sa3[x]
	else:
		back += sa3[x]
if max(chest, back, biceps) == chest:
	print('chest')
if max(chest, back, biceps) == back:
	print('back')
if max(chest, back, biceps) == biceps:
	print('biceps')


a = int(input())
h = list(map(int, input().split()))
c = sum([h[i] for i in range(0, a, 3)])
b = sum([h[i] for i in range(1, a, 3)])
ba = sum([h[i] for i in range(2, a, 3)])
if c > b and c > ba:
	print('chest')
elif b > ba:
	print('biceps')
else:
	print('back')


from operator import itemgetter
n = int(input())
ai = list(map(int, input().split()))
num = [[0, 'chest'], [0, 'biceps'], [0, 'back']]
for i in range(n):
	num[i % 3][0] += ai[i]
num.sort(key=itemgetter(0))
print(num[-1][1])


n = int(input())
l = list(map(int, input().rstrip().split()))
x = [0, 0, 0]
for i in range(n):
	if i % 3 == 0:
		x[0] += l[i]
	if i % 3 == 1:
		x[1] += l[i]
	if i % 3 == 2:
		x[2] += l[i]
d = {0: 'chest', 1: 'biceps', 2: 'back'}
print(d[x.index(max(x))])


n = int(input())
L = [int(x) for x in input().split()]
chest = 0
biceps = 0
back = 0
for i in range(n):
	if i % 3 == 0:
		chest += L[i]
	elif i % 3 == 1:
		biceps += L[i]
	else:
		back += L[i]
print('chest' if max(chest, biceps, back) == chest else 'biceps' if max(chest, biceps, back) == biceps else 'back')


n = int(input())
l = list(map(int, input().split()))
s = [sum(l[0::3]), sum(l[1::3]), sum(l[2::3])]
e = ['chest', 'biceps', 'back']
print(e[s.index(max(s))])


n = int(input())
l = list(map(int, input().split()))
check = 1
(biceps, back, chest) = (0, 0, 0)
for i in l:
	if check == 1:
		chest += i
		check = 2
	elif check == 2:
		biceps += i
		check = 3
	elif check == 3:
		back += i
		check = 1
k = [chest, biceps, back]
if max(k) == k[0]:
	print('chest')
elif max(k) == k[1]:
	print('biceps')
else:
	print('back')


a = {}
s = ['chest', 'biceps', 'back']
idx = 0
(a[s[0]], a[s[1]], a[s[2]]) = (0, 0, 0)
k = int(input())
n = list(map(int, input().split()))
for i in range(k):
	a[s[idx]] += n[i]
	if idx == 2:
		idx = -1
	idx += 1
l = [s[0], 0]
for i in s:
	if a[i] > l[1]:
		l[1] = a[i]
		l[0] = i
print(l[0])


no_of_exercises = int(input())
repeat_exer = list(map(int, input().split())) + [0] * (3 - no_of_exercises % 3)
chest = sum([repeat_exer[i] for i in range(0, no_of_exercises + 1, 3)])
biceps = sum([repeat_exer[i] for i in range(1, no_of_exercises + 1, 3)])
back = sum([repeat_exer[i] for i in range(2, no_of_exercises + 1, 3)])
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
a = [int(i) for i in input().split()]
c = [0, 0, 0]
for i in range(n):
	c[(i + 1) % 3 - 1] += a[i]
if c[0] > c[1] and c[0] > c[2]:
	print('chest')
elif c[1] > c[0] and c[1] > c[2]:
	print('biceps')
else:
	print('back')


t = int(input())
l = list(map(int, input().split()))
c = 0
bi = 0
b = 0
for i in range(0, t, 3):
	c = c + l[i]
	if i + 1 < t:
		bi = bi + l[i + 1]
	if i + 2 < t:
		b = b + l[i + 2]
if c > bi and c > b:
	print('chest')
if bi > c and bi > b:
	print('biceps')
if b > bi and b > c:
	print('back')


input()
l = list(map(int, input().split()))
c = 0
b = 0
back = 0
turn = 1
for i in l:
	if turn == 1:
		turn = 2
		c += i
	elif turn == 2:
		turn = 3
		b += i
	elif turn == 3:
		turn = 1
		back += i
if c > b and c > back:
	print('chest')
elif b > c and b > back:
	print('biceps')
else:
	print('back')


n = int(input())
p = list(map(int, input().split()))
c = 0
bic = 0
back = 0
if n == 1:
	c += p[0]
elif n == 2:
	c += p[0]
	bic += p[1]
else:
	for i in range(0, n, 3):
		c += p[i]
		if i + 1 < n:
			bic += p[i + 1]
		if i + 2 < n:
			back += p[i + 2]
d = {c: 'chest', bic: 'biceps', back: 'back'}
print(d[max(c, bic, back)])


n = int(input())
s = input().split()
A = [0, 0, 0]
for i in range(n):
	A[i % 3] += int(s[i])
m = max(A)
if m == A[0]:
	print('chest')
elif m == A[1]:
	print('biceps')
else:
	print('back')


d = {'chest': 0, 'biceps': 0, 'back': 0}
n = int(input())
p = input()
l = p.split()
for i in range(n):
	if i % 3 == 0:
		d['chest'] += int(l[i])
	elif i % 3 == 1:
		d['biceps'] += int(l[i])
	elif i % 3 == 2:
		d['back'] += int(l[i])
key_max = max(d.keys(), key=lambda k: d[k])
print(key_max)


ex = ['chest', 'biceps', 'back']
n = int(input())
lst = [int(i) for i in input().split(' ')]
c1 = 0
c2 = 0
c3 = 0
for i in range(n):
	if i % 3 == 0:
		c1 = c1 + lst[i]
	if i % 3 == 1:
		c2 = c2 + lst[i]
	if i % 3 == 2:
		c3 = c3 + lst[i]
if c1 > c2 and c1 > c3:
	print(ex[0])
if c2 > c3 and c2 > c1:
	print(ex[1])
if c3 > c1 and c3 > c2:
	print(ex[2])


n = int(input())
l = list(map(int, input().split()))
a = 0
b = 0
c = 0
for i in range(0, n, 3):
	a = a + l[i]
for i in range(1, n, 3):
	b = b + l[i]
for i in range(2, n, 3):
	c = c + l[i]
if max(a, b, c) is a:
	print('chest')
if max(a, b, c) is b:
	print('biceps')
if max(a, b, c) is c:
	print('back')


n = int(input())
a = list(map(int, input().split()))
q = len(a)
chest = []
biceps = []
back = []
for i in range(q):
	if i % 3 == 0:
		chest.append(a[i])
	elif i % 3 == 1:
		biceps.append(a[i])
	else:
		back.append(a[i])
x = sum(chest)
y = sum(biceps)
z = sum(back)
if max(x, y, z) == x:
	print('chest')
elif max(x, y, z) == y:
	print('biceps')
else:
	print('back')


n = int(input())
l = [0, 0, 0]
l1 = ['chest', 'biceps', 'back']
for (a, b) in enumerate(map(int, input().split(' '))):
	l[a % 3] += b
if l[0] > l[1] and l[0] > l[2]:
	print('chest')
elif l[1] > l[0] and l[1] > l[2]:
	print('biceps')
elif l[2] > l[0] and l[2] > l[1]:
	print('back')


a = int(input())
v = input().split()
i = 0
j = 1
k = 2
x = 0
y = 0
z = 0
while i < a:
	x = x + int(v[i])
	i = i + 3
while j < a:
	y = y + int(v[j])
	j = j + 3
while k < a:
	z = z + int(v[k])
	k = k + 3
if x > y and x > z:
	print('chest')
elif y > x and y > z:
	print('biceps')
elif z > x and z > y:
	print('back')


n = int(input())
(a, b, c) = (0, 0, 0)
v = list(map(int, input().split()))
for x in range(0, n, 3):
	a += v[x]
for x in range(1, n, 3):
	b += v[x]
for x in range(2, n, 3):
	c += v[x]
if a > b and a > c:
	print('chest')
elif b > c and b > a:
	print('biceps')
else:
	print('back')


trains = int(input())
times = [int(t) for t in input().split()]
(c, b, bc, timer) = (0, 0, 0, 0)
for i in times:
	timer += 1
	if timer % 3 == 1:
		c += i
	elif timer % 3 == 2:
		b += i
	else:
		(timer, bc) = (0, bc + i)
if c > b and c > bc:
	print('chest')
else:
	print('biceps' if b > bc else 'back')


input()
a = [0, 0, 0]
s = 0
for i in input().split():
	a[s % 3] += int(i)
	s += 1
i = a.index(max(a))
if i == 0:
	print('chest')
elif i == 1:
	print('biceps')
else:
	print('back')


n = int(input())
exercise = list(map(int, input().split()))
cnt = [0, 0, 0]
for i in range(n):
	cnt[i % 3] += exercise[i]
if max(cnt) == cnt[0]:
	print('chest')
elif max(cnt) == cnt[1]:
	print('biceps')
else:
	print('back')


x = input()
del x
b = [int(i) for i in input().split()]
(s1, s2, s3) = (sum(b[::3]), sum(b[1::3]), sum(b[2::3]))
if s1 > s2 and s1 > s3:
	print('chest')
if s2 > s1 and s2 > s3:
	print('biceps')
if s3 > s1 and s3 > s2:
	print('back')


def main():
	ex = [0, 0, 0]
	n = int(input())
	arr = [int(x) for x in input().strip().split(' ')]
	for i in range(n):
		ex[i % 3] += arr[i]
	if ex[0] > ex[1] and ex[0] > ex[2]:
		print('chest')
	if ex[1] > ex[2] and ex[1] > ex[0]:
		print('biceps')
	if ex[2] > ex[1] and ex[2] > ex[0]:
		print('back')
main()


n = int(input())
li = list(input().split())
li1 = [0, 0, 0]
li2 = ['chest', 'biceps', 'back']
for (i, j) in enumerate(li):
	li1[int(i) % 3] += int(j)
print(li2[li1.index(max(li1))])


x = int(input())
y = [int(a) for a in input().split()]
a = []
b = []
c = []
for i in range(x):
	if i % 3 == 0:
		a.append(y[i])
	if i % 3 == 1:
		b.append(y[i])
	if i % 3 == 2:
		c.append(y[i])
s1 = sum(a)
s2 = sum(b)
s3 = sum(c)
if s1 > s2 and s1 > s3:
	print('chest')
elif s2 > s1 and s2 > s3:
	print('biceps')
else:
	print('back')


n = int(input().strip())
arr = list(map(int, input().strip().split(' ')))
(sum_chest, sum_bicep, sum_back) = (0, 0, 0)
for i in range(n):
	if i % 3 == 0:
		sum_chest += arr[i]
	elif i % 3 == 1:
		sum_bicep += arr[i]
	elif i % 3 == 2:
		sum_back += arr[i]
list1 = [sum_chest, sum_bicep, sum_back]
if max(list1) == sum_chest:
	print('chest')
elif max(list1) == sum_bicep:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
(c, j) = (0, 0)
(p, k) = (0, 1)
(b, l) = (0, 2)
for i in range(n):
	if i == j:
		c += a[i]
		j += 3
	if i == k:
		p += a[i]
		k += 3
	if i == l:
		b += a[i]
		l += 3
x = max(c, b, p)
if c == x:
	print('chest')
elif p == x:
	print('biceps')
else:
	print('back')


n = int(input().strip())
a = list(map(int, input().split()))
chestn = sum(a[0::3])
bicepsn = sum(a[1::3])
backn = sum(a[2::3])
if chestn > bicepsn:
	if backn > chestn:
		print('back')
	else:
		print('chest')
elif bicepsn > backn:
	print('biceps')
else:
	print('back')


(c, bi, ba) = ([], [], [])
s = 'back'
a = int(input())
ex = list(map(int, input().strip().split()))
for i in range(len(ex)):
	if i % 3 == 0:
		c.append(ex[i])
	elif i % 3 == 1:
		bi.append(ex[i])
	else:
		ba.append(ex[i])
x = sum(c)
y = sum(bi)
z = sum(ba)
if x > y:
	if x > z:
		s = 'chest'
elif y > z:
	s = 'biceps'
print(s)


n = int(input())
L = list(map(int, input().split()))
(a, b, c) = (sum(L[0::3]), 0, 0)
if len(L) > 1:
	b = sum(L[1::3])
if len(L) > 2:
	c = sum(L[2::3])
if a > b and a > c:
	print('chest')
elif b > a and b > c:
	print('biceps')
elif c > a and c > b:
	print('back')


n = int(input())
exercise = {'chest': 0, 'biceps': 0, 'back': 0}
for (i, j) in enumerate((int(i) for i in input().split())):
	if i % 3 == 0:
		exercise['chest'] += j
	elif i % 3 == 1:
		exercise['biceps'] += j
	else:
		exercise['back'] += j
print(max((i for (i, j) in exercise.items() if j == max(exercise.values()))))


n = int(input())
a = list(map(int, input().split()))
e = {'biceps': 0, 'chest': 0, 'back': 0}
curr = 'chest'
for i in range(n):
	e[curr] += a[i]
	if curr == 'chest':
		curr = 'biceps'
	elif curr == 'biceps':
		curr = 'back'
	else:
		curr = 'chest'
k = max(e, key=e.get)
print(k)


x = int(input())
y = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
for i in range(x):
	if i % 3 == 0:
		chest = chest + y[i]
	elif i % 3 == 1:
		biceps = biceps + y[i]
	else:
		back = back + y[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


s = [0, 3, 6, 9, 12, 15, 18]
p = [1, 4, 7, 10, 13, 16, 19]
q = [2, 5, 8, 11, 14, 17, 20]
x = int(input())
g = h = i = 0
z = [int(n) for n in input().split()]
v = []
for n in range(x):
	if s.count(n) == 1:
		g += z[n]
	elif p.count(n) == 1:
		h += z[n]
	elif q.count(n) == 1:
		i += z[n]
v.append(g)
v.append(h)
v.append(i)
if max(v) == v[0]:
	print('chest')
elif max(v) == v[1]:
	print('biceps')
else:
	print('back')


n = input()
l = list(map(int, input().split()))
val = [0, 0, 0]
j = 0
ans = ['chest', 'biceps', 'back']
for i in l:
	val[j % 3] += i
	j += 1
print(ans[val.index(max(val))])


n = int(input())
l1 = [int(i) for i in input().split()]
(a, b, c) = ([], [], [])
for i in range(n):
	if i % 3 == 0:
		a.append(l1[i])
	elif i % 3 == 1:
		b.append(l1[i])
	elif i % 3 == 2:
		c.append(l1[i])
(x, y, z) = (sum(a), sum(b), sum(c))
if x > y and x > z:
	print('chest')
elif y > x and y > z:
	print('biceps')
elif z > x and z > y:
	print('back')


n = int(input())
x = list(map(int, input().split()))
c = {'chest': 0, 'biceps': 0, 'back': 0}
count = 0
for i in x:
	if count == 0:
		c['chest'] += i
		count += 1
	elif count == 1:
		c['biceps'] += i
		count += 1
	elif count == 2:
		c['back'] += i
		count = 0
print(list(c.keys())[list(c.values()).index(max(c['biceps'], c['chest'], c['back']))])


def solve(arr, n):
	r = [0] * 3
	for i in range(n):
		r[i % 3] += arr[i]
	if r[0] > r[1] and r[0] > r[2]:
		return 'chest'
	elif r[1] > r[2] and r[1] > r[0]:
		return 'biceps'
	else:
		return 'back'
n = int(input())
arr = list(map(int, input().strip().split()))
result = solve(arr, n)
print(result)


n = int(input())
al = list(map(int, input().split()))
ex = [0, 0, 0]
exn = ['chest', 'biceps', 'back']
for (idx, a) in enumerate(al):
	ex[idx % 3] += a
print(exn[ex.index(max(ex))])


n = int(input())
l = list(map(int, input().split()))
(c1, c2, c3) = (0, 0, 0)
if len(l) % 3 == 1:
	l.append(0)
	l.append(0)
elif len(l) % 3 == 2:
	l.append(0)
for i in range(0, len(l), 3):
	c1 += l[i]
	c2 += l[i + 1]
	c3 += l[i + 2]
if c1 > c2 and c1 > c3:
	print('chest')
elif c2 > c3 and c2 > c1:
	print('biceps')
else:
	print('back')


n = int(input())
x = [int(i) for i in input().split()]
length = len(x)
chest = biceps = back = 0
for i in range(0, length, 3):
	chest += x[i]
for i in range(1, length, 3):
	biceps += x[i]
for i in range(2, length, 3):
	back += x[i]
if chest > biceps and chest > back:
	print('chest')
if biceps > chest and biceps > back:
	print('biceps')
if back > chest and back > biceps:
	print('back')


t = int(input())
l = list(map(int, input().split()))
chest = 0
bicep = 0
back = 0
for i in range(1, len(l) + 1):
	if i % 3 == 1:
		chest += l[i - 1]
	elif i % 3 == 2:
		bicep += l[i - 1]
	else:
		back += l[i - 1]
m = max(chest, bicep, back)
if m == back:
	print('back')
elif m == chest:
	print('chest')
else:
	print('biceps')


n = int(input())
b = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
u = 0
for i in range(n):
	if u == 0:
		chest += b[i]
		u += 1
	elif u == 1:
		biceps += b[i]
		u += 1
	else:
		back += b[i]
		u = 0
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
x = list(map(int, input().split()))
(chest, bic, back) = (0, 0, 0)
for a in range(n):
	if a % 3 == 0:
		chest += x[a]
	elif a % 3 == 1:
		bic += x[a]
	else:
		back += x[a]
if chest > bic and chest > back:
	print('chest')
elif bic > back and bic > chest:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
biceps = back = 0
chest = sum(l[0::3])
if n > 1:
	biceps = sum(l[1::3])
if n > 2:
	back = sum(l[2::3])
if chest > biceps and chest > back:
	print('chest')
elif biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
b = [0] * 3
for i in range(n):
	b[i % 3] += a[i]
(chest, biceps, back) = b
if chest > back and chest > biceps:
	print('chest')
if biceps > back and biceps > chest:
	print('biceps')
if back > biceps and back > chest:
	print('back')


import sys
input = sys.stdin.readline
n = int(input())
lt = list(map(int, input().split()))
chest = [lt[i] for i in range(0, n, 3)]
biceps = [lt[i] for i in range(1, n, 3)]
back = [lt[i] for i in range(2, n, 3)]
total = list()
total.append(sum(chest))
total.append(sum(biceps))
total.append(sum(back))
if total.index(max(total)) == 0:
	print('chest')
elif total.index(max(total)) == 1:
	print('biceps')
else:
	print('back')


n = input()
n = int(n)
l = [0 for i in range(n)]
l = list(map(int, input().split(' ')))
m = [0, 0, 0]
(i, j) = (0, 0)
while i < n:
	j = j % 3
	m[j] += l[i]
	j += 1
	i += 1
tmp = m.index(max(m))
if tmp == 0:
	print('chest')
elif tmp == 1:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
a1 = 0
a2 = 0
a3 = 0
a4 = []
for i in range(0, n, 3):
	a1 += a[i]
for i in range(1, n, 3):
	a2 += a[i]
for i in range(2, n, 3):
	a3 += a[i]
a4 = [a1, a2, a3]
if a4.index(max(a4)) == 0:
	print('chest')
elif a4.index(max(a4)) == 1:
	print('biceps')
elif a4.index(max(a4)) == 2:
	print('back')


n = int(input())
a = [int(a) for a in input().split()]
c = 0
b = 0
d = 0
count = 1
for i in range(len(a)):
	if count == 1:
		c += a[i]
		count += 1
	elif count == 2:
		b += a[i]
		count += 1
	else:
		d += a[i]
		count = 1
if c > b and c > d:
	print('chest')
elif b > c and b > d:
	print('biceps')
else:
	print('back')


n = int(input())
e = list(map(int, input().split()))
(c, bi, b) = (0, 0, 0)
for i in range(0, n, 3):
	l = e[i:i + 3]
	try:
		c += l[0]
		bi += l[1]
		b += l[2]
	except Exception:
		pass
x = max(c, bi, b)
if x == c:
	print('chest')
elif x == bi:
	print('biceps')
else:
	print('back')


t = int(input())
l = list(map(int, input().split()))
c = 0
b = 0
h = 0
for i in range(0, t, 3):
	try:
		c = c + l[i]
		b = b + l[i + 1]
	except:
		pass
h = sum(l) - c - b
if c > b and c > h:
	print('chest')
elif b > c and b > h:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
i = 0
(s1, s2, s3) = (0, 0, 0)
p1 = 1
p2 = 2
p3 = 3
(i1, i2, i3) = (0, 0, 0)
for i in range(len(l)):
	if i + 1 == p1 + 3 * i1:
		s1 += l[i]
		i1 += 1
	elif i + 1 == p2 + 3 * i2:
		s2 += l[i]
		i2 += 1
	elif i + 1 == p3 + 3 * i3:
		s3 += l[i]
		i3 += 1
if s1 >= s2 and s1 >= s3:
	print('chest')
elif s2 >= s1 and s2 >= s3:
	print('biceps')
elif s3 >= s1 and s3 >= s2:
	print('back')


n = int(input())
ar = [int(i) for i in input().split()]
ch = 0
bi = 0
ba = 0
for i in range(n):
	if i % 3 == 0:
		ch += ar[i]
	elif i % 3 == 1:
		bi += ar[i]
	else:
		ba += ar[i]
if ch == max(ch, bi, ba):
	print('chest')
elif bi == max(ch, bi, ba):
	print('biceps')
else:
	print('back')


a = int(input())
(list, chest, biceps, back, i) = ([], [], [], [], 0)
list = [int(x) for x in input().split()]
while i < a:
	try:
		chest.append(list[3 * i])
		biceps.append(list[3 * i + 1])
		back.append(list[3 * i + 2])
		i = i + 1
	except:
		i = i + 1
		continue
c = max(sum(chest), sum(biceps), sum(back))
if c == sum(chest):
	print('chest')
elif c == sum(biceps):
	print('biceps')
else:
	print('back')


t = int(input())
x = list(map(int, input().split()))
ch = 0
bi = 0
ba = 0
for i in range(0, len(x), 3):
	ch += x[i]
for i in range(1, len(x), 3):
	bi += x[i]
for i in range(2, len(x), 3):
	ba += x[i]
m = max(ch, bi, ba)
if m == ch:
	print('chest')
elif m == bi:
	print('biceps')
else:
	print('back')


n = input()
chest = 0
biceps = 0
back = 0
a = list(map(int, input().split()))
for i in range(len(a)):
	if i % 3 == 0:
		chest += a[i]
	elif i % 3 == 1:
		biceps += a[i]
	else:
		back += a[i]
Max = max(chest, biceps, back)
if Max == chest:
	print('chest')
elif Max == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
chest = a[::3]
biceps = a[1::3]
back = a[2::3]
ch = sum(chest)
bic = sum(biceps)
back = sum(back)
if ch > bic and ch > back:
	print('chest')
elif bic > ch and bic > back:
	print('biceps')
else:
	print('back')


n = input()
l = list(map(int, input().split()))
(a, b, c) = (0, 0, 0)
(chest, bicep, back) = (0, 1, 2)
for i in range(len(l)):
	if i == chest:
		a += l[i]
		chest += 3
	elif i == bicep:
		b += l[i]
		bicep += 3
	else:
		c += l[i]
		back += 3
result = max(a, b, c)
if result == a:
	print('chest')
elif result == b:
	print('biceps')
else:
	print('back')


def read():
	inputs = input().strip()
	return list(map(int, inputs.split()))

def read_pair():
	return map(int, input().split(' '))
n = int(input())
a = read()
b = [0] * 5
for i in range(n):
	if i % 3 == 0:
		b[0] += a[i]
	elif i % 3 == 1:
		b[1] += a[i]
	else:
		b[2] += a[i]
if max(b[0], max(b[1], b[2])) == b[0]:
	print('chest')
elif max(b[0], max(b[1], b[2])) == b[1]:
	print('biceps')
else:
	print('back')


import sys
import math
import bisect

def main():
	s = ['chest', 'biceps', 'back']
	B = [0] * 3
	n = int(input())
	A = list(map(int, input().split()))
	for i in range(n):
		B[i % 3] += A[i]
	for i in range(3):
		if B[i] == max(B):
			print(s[i])
main()


def ii():
	return int(input())

def mi():
	return map(int, input().split())

def li():
	return list(mi())
n = ii()
a = li()
c = b = ba = 0
for i in range(n):
	if i % 3 == 0:
		c += a[i]
	elif i % 3 == 1:
		b += a[i]
	else:
		ba += a[i]
if c > b and c > ba:
	print('chest')
elif b > c and b > ba:
	print('biceps')
else:
	print('back')


podhodi = int(input())
uprazhnenia = list(map(int, input().split()))
turn = biceps = back = chest = 0
for i in range(podhodi):
	turn += 1
	if turn == 1:
		chest += uprazhnenia[i]
	elif turn == 2:
		biceps += uprazhnenia[i]
	else:
		back += uprazhnenia[i]
		turn = 0
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
s = input()
s = s.split()
i = 0
chest = 0
biceps = 0
back = 0
while i < n:
	chest += int(s[i])
	if i + 1 < n:
		biceps += int(s[i + 1])
	if i + 2 < n:
		back += int(s[i + 2])
	i += 3
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
ans = dict.fromkeys(['chest', 'biceps', 'back'], 0)
for i in range(n):
	if i % 3 == 0:
		ans['chest'] += a[i]
	elif i % 3 == 1:
		ans['biceps'] += a[i]
	else:
		ans['back'] += a[i]
for key in ans:
	if ans[key] == max(ans.values()):
		print(key)


a = int(input())
c = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
key = 1
for i in c:
	if key == 1:
		chest += i
		key += 1
	elif key == 2:
		biceps += i
		key += 1
	else:
		back += i
		key = 1
e = max(chest, biceps, back)
if e == chest:
	print('chest')
elif e == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
alist = list(map(int, input().split()))
sumc = 0
sumb = 0
sumbk = 0
for i in range(0, n, 3):
	sumc += alist[i]
if n > 1:
	for j in range(1, n, 3):
		sumb += alist[j]
	if n > 2:
		for i in range(2, n, 3):
			sumbk += alist[i]
sumf = max(sumc, sumb, sumbk)
if sumf == sumc:
	print('chest')
elif sumf == sumb:
	print('biceps')
else:
	print('back')


n = int(input())
s = list(map(int, input().split()))
ch = 0
bi = 0
ba = 0
c = 0
for i in s:
	try:
		ch = ch + int(s[c])
		c += 1
	except:
		break
	try:
		bi = bi + int(s[c])
		c += 1
	except:
		break
	try:
		ba = ba + int(s[c])
		c += 1
	except:
		break
if bi < ch > ba:
	print('chest')
if ch < bi > ba:
	print('biceps')
if ch < ba > bi:
	print('back')


t = int(input())
n = list(map(int, input().split()))
a = 0
b = 0
c = 0
i = 0
while i < t:
	a = a + n[i]
	if i + 1 < t:
		b = b + n[i + 1]
	if i + 2 < t:
		c = c + n[i + 2]
	i = i + 3
dic = {'chest': a, 'biceps': b, 'back': c}
print(max(dic, key=dic.get))


n = int(input())
l = list(map(int, input().split()))
sum1 = 0
sum2 = 0
sum3 = 0
for i in range(0, n, 3):
	sum1 = sum1 + l[i]
for i in range(1, n, 3):
	sum2 = sum2 + l[i]
for i in range(2, n, 3):
	sum3 = sum3 + l[i]
if sum1 > sum2 and sum1 > sum3:
	print('chest')
elif sum2 > sum3 and sum2 > sum3:
	print('biceps')
else:
	print('back')


hat = int(input())
lst = [int(x) for x in input().split()]
chest = 0
bi = 0
back = 0
counter = 0
for i in lst:
	if counter == 0:
		chest += i
		counter += 1
	elif counter == 1:
		bi += i
		counter += 1
	elif counter == 2:
		back += i
		counter = 0
if chest == max(chest, bi, back):
	print('chest')
elif bi == max(chest, bi, back):
	print('biceps')
elif back == max(chest, bi, back):
	print('back')


input()
a = [0, 0, 0]
s = ['chest', 'biceps', 'back']
arr = list(map(int, input().split()))
for i in range(len(arr)):
	a[i % 3] += arr[i]
print(s[a.index(max(a))])


n = int(input())
days = [int(n) for n in input().split()]
chest = 0
biceps = 0
back = 0
for i in range(n):
	if i % 3 == 0:
		chest += days[i]
	elif i % 3 == 1:
		biceps += days[i]
	else:
		back += days[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = input()
ec = [0] * 3
(maxi, maxv) = (0, 0)
for (i, v) in enumerate(map(int, input().split())):
	i %= 3
	ec[i] += v
	if ec[i] > maxv:
		maxi = i
		maxv = ec[i]
print(('chest', 'biceps', 'back')[maxi])


a = int(input())
b = list(map(int, input().split()))
chest = 0
bicep = 0
back = 0
j = 0
for i in range(len(b)):
	if j == 0:
		chest += b[i]
		j = 1
	elif j == 1:
		bicep += b[i]
		j = 2
	elif j == 2:
		back += b[i]
		j = 0
if bicep > chest and bicep > back:
	print('biceps')
elif bicep < chest and chest > back:
	print('chest')
else:
	print('back')


N = int(input())
a = list(map(int, input().split()))
a.append(0)
a.append(0)
a.append(0)
B = C = D = 0
b = 0
c = 1
d = 2
for i in range(N // 3 + 1):
	B += a[b]
	C += a[c]
	D += a[d]
	b += 3
	c += 3
	d += 3
if B == max(B, C, D):
	print('chest')
elif C == max(B, C, D):
	print('biceps')
else:
	print('back')


n = int(input())
n1 = list(map(int, input().split()))
s1 = 0
s2 = 0
s3 = 0
for i in range(0, len(n1), 3):
	s1 = s1 + n1[i]
for i in range(1, len(n1), 3):
	s2 = s2 + n1[i]
for i in range(2, len(n1), 3):
	s3 = s3 + n1[i]
s = [s1, s2, s3]
a = max(s)
if a == s1:
	print('chest')
if a == s2:
	print('biceps')
if a == s3:
	print('back')


n = int(input())
l = list(map(int, input().split()))
p = []
count1 = 0
count2 = 0
count3 = 0
for i in range(0, n, 3):
	count1 += l[i]
p.append(count1)
for j in range(1, n, 3):
	count2 += l[j]
p.append(count2)
for k in range(2, n, 3):
	count3 += l[k]
p.append(count3)
max_ = max(p)
if max_ == p[0]:
	print('chest')
elif max_ == p[1]:
	print('biceps')
elif max_ == p[2]:
	print('back')


n = int(input())
a = list(map(int, input().split()))
chest = []
biceps = []
back = []
c = 0
for i in range(len(a)):
	if c % 3 == 0:
		chest.append(a[i])
		c += 1
	elif c % 3 == 1:
		biceps.append(a[i])
		c += 1
	elif c % 3 == 2:
		back.append(a[i])
		c += 1
q = sum(chest)
w = sum(biceps)
e = sum(back)
if q > w and q > e:
	print('chest')
elif w > q and w > e:
	print('biceps')
else:
	print('back')


trash = int(input())
firstLine = [int(n) for n in input().split()]
temp = [0, 0, 0]
for i in range(0, len(firstLine)):
	if (i + 1) % 3 == 2:
		temp[1] += firstLine[i]
	elif (i + 1) % 3 == 1:
		temp[0] += firstLine[i]
	else:
		temp[2] += firstLine[i]
if temp.index(max(temp)) == 0:
	print('chest')
elif temp.index(max(temp)) == 1:
	print('biceps')
elif temp.index(max(temp)) == 2:
	print('back')


input()
ls = list(map(int, input().split()))
vals = [sum(ls[::3]), sum(ls[1::3]), sum(ls[2::3])]
print(['chest', 'biceps', 'back'][vals.index(max(vals))])


n = int(input())
l = list(map(int, input().split()))
p1 = l[0:n:3]
p2 = l[1:n:3]
p3 = l[2:n:3]
a = sum(p1)
b = sum(p2)
c = sum(p3)
d = max(a, b, c)
if a == d:
	print('chest')
elif b == d:
	print('biceps')
else:
	print('back')


a = int(input())
n = 0
chest = 0
biceps = 0
back = 0
b = input().split()
for i in range(a):
	if n == 0:
		chest += int(b[i])
		n += 1
	elif n == 1:
		biceps += int(b[i])
		n += 1
	else:
		back += int(b[i])
		n = 0
if chest > back and chest > biceps:
	print('chest')
elif back > chest and back > biceps:
	print('back')
else:
	print('biceps')


s = int(input())
l = list(map(int, input().strip().split()[:s]))
bicep = chest = back = 0
if len(l) % 3 != 0:
	for x in range(3 - len(l) % 3):
		l.append(0)
x = 0
while x < len(l):
	chest += l[x]
	bicep += l[x + 1]
	back += l[x + 2]
	x += 3
if max(chest, bicep, back) == chest:
	print('chest')
elif max(chest, bicep, back) == bicep:
	print('biceps')
else:
	print('back')


n = int(input())
exe = input()
exe = exe.split()
exe = [int(x) for x in exe]
chest = 0
biceps = 0
back = 0
if n >= 3:
	chest = sum(exe[0::3])
	biceps = sum(exe[1::3])
	back = sum(exe[2::3])
if n == 2:
	chest = exe[0]
	biceps = exe[1]
if n == 1:
	chest = exe[0]
if chest >= biceps and chest > back:
	print('chest')
if biceps >= chest and biceps >= back:
	print('biceps')
if back >= chest and back >= biceps:
	print('back')


n = int(input())
g = []
x = 0
y = 1
z = 2
c = 0
b = 0
ba = 0
for i in range(n):
	a = map(int, input().split())
	g += a
	break
for u in range(len(g)):
	if u == x:
		c += g[x]
		x += 3
	elif u == y:
		b += g[y]
		y += 3
	elif u == z:
		ba += g[z]
		z += 3
if c > b and c > ba:
	print('chest')
elif b > c and b > ba:
	print('biceps')
elif ba > c and ba > b:
	print('back')


n = int(input())
l = [int(i) for i in input().split()]
c = 0
bi = 0
ba = 0
for i in range(n):
	if i % 3 == 0:
		c += l[i]
	elif i % 3 == 1:
		bi += l[i]
	elif i % 3 == 2:
		ba += l[i]
if max(c, bi, ba) == c:
	print('chest')
elif max(c, bi, ba) == bi:
	print('biceps')
elif max(c, bi, ba) == ba:
	print('back')


n = int(input())
l = list(map(int, input().split()))
ex = ['chest', 'biceps', 'back']
m = [0, 0, 0]
for i in range(len(l)):
	m[i % 3] += l[i]
print(ex[m.index(max(m))])


input()
a = list(map(int, input().split()))
chest = biceps = back = 0
for i in range(0, len(a)):
	if i % 3 == 2:
		back += a[i]
	elif i % 3 == 1:
		biceps += a[i]
	else:
		chest += a[i]
if back > biceps and back > chest:
	print('back')
	exit()
print('chest' if chest > back and chest > biceps else 'biceps')


nums = input().split(' ')
nums = int(nums[0])
ks = input().split(' ')
ks = [int(ks[i]) for i in range(nums)]
st_1 = ks[0:nums:3]
st_2 = ks[1:nums:3]
st_3 = ks[2:nums:3]
sum_1 = sum(st_1)
sum_2 = sum(st_2)
sum_3 = sum(st_3)
max_sum = max(sum_1, sum_2, sum_3)
if max_sum == sum_1:
	print('chest')
elif max_sum == sum_2:
	print('biceps')
elif max_sum == sum_3:
	print('back')


n = int(input())
line = [int(e) for e in input().split(' ')]
L = [sum((line[k] for k in range(0, n, 3))), sum((line[k] for k in range(1, n, 3))), sum((line[k] for k in range(2, n, 3)))]
print(['chest', 'biceps', 'back'][L.index(max(L))])


n_val = int(input())
exercises = list(map(int, input().split()))
idx = 0
total = [0, 0, 0]
for idx in range(n_val):
	total[idx % 3] += exercises[idx]
if total[0] > total[1]:
	if total[0] > total[2]:
		print('chest')
	else:
		print('back')
elif total[1] > total[2]:
	print('biceps')
else:
	print('back')


n = int(input())
arr = [int(x) for x in input().split()]
(chest, biceps, back) = (0, 0, 0)
for i in range(len(arr)):
	if i % 3 == 0:
		chest += arr[i]
	elif i % 3 == 1:
		biceps += arr[i]
	else:
		back += arr[i]
ans = max(chest, biceps, back)
if ans == chest:
	print('chest')
elif ans == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
arr = [int(x) for x in input().split()]
(chest, biceps, back) = (sum(arr[::3]), sum(arr[1::3]), sum(arr[2::3]))
if chest > biceps and chest > back:
	print('chest')
elif chest < biceps and biceps > back:
	print('biceps')
else:
	print('back')


a = int(input())
l = [int(i) for i in input().split()]
biceps = 0
back = 0
chest = 0
for i in range(0, len(l), 3):
	chest += l[i]
for j in range(1, len(l), 3):
	biceps += l[j]
for k in range(2, len(l), 3):
	back += l[k]
rep = max(chest, biceps, back)
if rep == chest:
	print('chest')
elif rep == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
exercise = [0, 0, 0]
inputs = [int(x) for x in input().split()]
maxExe = 0
maxMus = 0
for i in range(0, n):
	j = i % 3
	exercise[j] += inputs[i]
	if exercise[j] > maxExe:
		maxExe = exercise[j]
		maxMus = j
if maxMus == 0:
	print('chest')
elif maxMus == 1:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
m = len(a)
k = []
chest = []
biceps = []
back = []
for i in range(m):
	back = a[2::3]
	biceps = a[1::3]
	chest = a[::3]
if sum(back) >= sum(chest) and sum(back) >= sum(biceps):
	print('back')
if sum(chest) >= sum(back) and sum(chest) >= sum(biceps):
	print('chest')
if sum(biceps) >= sum(chest) and sum(biceps) >= sum(back):
	print('biceps')


import sys, math
input = sys.stdin.readline

def inp():
	return int(input())

def inara():
	return list(map(int, input().split()))

def insr():
	s = input()
	return list(s[:len(s) - 1])

def invr():
	return map(int, input().split())
n = inp()
ara = inara()
one = 0
two = 0
three = 0
for i in range(0, n, 3):
	one += ara[i]
for i in range(1, n, 3):
	two += ara[i]
for i in range(2, n, 3):
	three += ara[i]
ans = max(one, two, three)
if ans == one:
	print('chest')
elif ans == two:
	print('biceps')
else:
	print('back')


t = int(input())
l = list(map(int, input().split()))
countc = 0
countbi = 0
countb = 0
for i in range(0, t, 3):
	countc += l[i]
	if i + 1 < t:
		countbi += l[i + 1]
	if i + 2 < t:
		countb += l[i + 2]
if max(countc, countbi, countb) == countc:
	print('chest')
elif max(countc, countbi, countb) == countbi:
	print('biceps')
elif max(countc, countbi, countb) == countb:
	print('back')


n = int(input())
a = list(map(int, input().split()))
b = [0] * 3
for i in range(n):
	b[i % 3] += a[i]
mx = max(b)
if b[0] == mx:
	print('chest')
elif b[1] == mx:
	print('biceps')
else:
	print('back')


import sys
from math import *

def minp():
	return sys.stdin.readline().strip()

def mint():
	return int(minp())

def mints():
	return map(int, minp().split())
n = mint()
a = [0, 0, 0]
j = 0
for i in mints():
	a[j] += i
	j = (j + 1) % 3
i = a.index(max(a))
print(['chest', 'biceps', 'back'][i])


n = int(input())
v = []
u = []
t = []
l = list(map(int, input().split()))
for i in range(0, n, 3):
	v.append(l[i])
for i in range(1, n, 3):
	u.append(l[i])
for i in range(2, n, 3):
	t.append(l[i])
vs = sum(v)
ts = sum(t)
us = sum(u)
h = max(vs, us, ts)
if h == vs:
	print('chest')
elif h == us:
	print('biceps')
else:
	print('back')


n = int(input())
a = [int(i) for i in input().split()]
h = k = l = 0
for i in range(n):
	if i % 3 == 0:
		h += a[i]
	elif i % 3 == 1:
		k += a[i]
	else:
		l += a[i]
if h > k:
	if l > h:
		print('back')
	else:
		print('chest')
elif l > k:
	print('back')
else:
	print('biceps')


def main():
	n = int(input())
	a = list(map(int, input().split()))
	chest = 0
	back = 0
	biceps = 0
	for i in range(n):
		if i % 3 == 0:
			chest += a[i]
		elif i % 3 == 1:
			biceps += a[i]
		elif i % 3 == 2:
			back += a[i]
	result = [('chest', chest), ('biceps', biceps), ('back', back)]
	return sorted(result, key=lambda x: x[1])[-1][0]
print(main())


while True:
	try:
		s = input()
		s = list(map(int, input().split(' ')))
		(a, b, c) = (True, False, False)
		(l1, l2, l3) = (0, 0, 0)
		for i in s:
			if a:
				l1 += i
				(a, b, c) = (False, True, False)
			elif b:
				l2 += i
				(a, b, c) = (False, False, True)
			else:
				l3 += i
				(a, b, c) = (True, False, False)
		if max(l1, l2, l3) == l1:
			print('chest')
		elif max(l1, l2, l3) == l2:
			print('biceps')
		else:
			print('back')
	except:
		break


import sys
from functools import reduce
from collections import Counter
import time
import datetime
import math

def ip():
	return int(sys.stdin.readline())

def sip():
	return sys.stdin.readline()

def mip():
	return map(int, sys.stdin.readline().split())

def mips():
	return map(str, sys.stdin.readline().split())

def lip():
	return list(map(int, sys.stdin.readline().split()))

def matip(n, m):
	lst = []
	for i in range(n):
		arr = lip()
		lst.insert(i, arr)
	return lst

def factors(n):
	return list(set(reduce(list.__add__, ([i, n // i] for i in range(1, int(n ** 0.5) + 1) if n % i == 0))))

def minJumps(arr, n):
	jumps = [0 for i in range(n)]
	if n == 0 or arr[0] == 0:
		return float('inf')
	jumps[0] = 0
	for i in range(1, n):
		jumps[i] = float('inf')
		for j in range(i):
			if i <= j + arr[j] and jumps[j] != float('inf'):
				jumps[i] = min(jumps[i], jumps[j] + 1)
				break
	return jumps[n - 1]

def dic(arr):
	return Counter(arr)

def check_prime(n):
	if n < 2:
		return False
	for i in range(2, int(n ** 0.5) + 1, 2):
		if n % i == 0:
			return False
	return True
n = ip()
arr = lip()
c = 0
b = 0
ba = 0
for i in range(n):
	if i % 3 == 0:
		c += arr[i]
	elif i % 3 == 1:
		b += arr[i]
	else:
		ba += arr[i]
if c > b and c > ba:
	print('chest')
elif b > c and b > ba:
	print('biceps')
else:
	print('back')


n = int(input())
arr = [int(x) for x in input().split()]
sum1 = 0
sum2 = 0
sum3 = 0
for i in range(0, len(arr), 3):
	sum1 += arr[i]
for j in range(1, len(arr), 3):
	sum2 += arr[j]
for k in range(2, len(arr), 3):
	sum3 += arr[k]
if sum1 > sum2 and sum1 > sum3:
	print('chest')
elif sum2 > sum1 and sum2 > sum3:
	print('biceps')
else:
	print('back')


n = int(input())
tren = list(map(int, input().split()))
grud = 0
bic = 0
spin = 0
upr = 1
for i in tren:
	if upr == 1:
		grud += i
	elif upr == 2:
		bic += i
	elif upr == 3:
		spin += i
	upr += 1
	if upr > 3:
		upr = 1
if bic < grud > spin:
	print('chest')
elif grud < bic > spin:
	print('biceps')
elif bic < spin > grud:
	print('back')


import math
from operator import itemgetter

def get_primes(prime_supr):
	is_prime = [0] * 2 + [1] * prime_supr
	for i in range(2, int(math.sqrt(prime_supr)) + 1):
		if is_prime[i]:
			for j in range(i * i, prime_supr + 1, i):
				is_prime[j] = 0
	return is_prime
get_int = lambda : map(int, input().split())
n = int(input())
a = list(get_int())
b = [0, 0, 0]
for i in range(n):
	b[i % 3] += a[i]
if b[0] == max(b):
	print('chest')
elif b[1] == max(b):
	print('biceps')
else:
	print('back')


tasks = {'chest': 0, 'biceps': 0, 'back': 0}
n = int(input())
a = [int(elem) for elem in input().split()]
for i in range(n):
	if i % 3 == 0:
		tasks['chest'] += a[i]
	if i % 3 == 1:
		tasks['biceps'] += a[i]
	if i % 3 == 2:
		tasks['back'] += a[i]
for (name, counts) in tasks.items():
	if counts == max(tasks.values()):
		print(name)


n = int(input())
k = list(map(int, input().strip().split()))
c = 0
l = 0
f = 0
for i in range(0, len(k), 3):
	c += k[i]
for i in range(1, len(k), 3):
	l += k[i]
for i in range(2, len(k), 3):
	f += k[i]
if c > l and c > f:
	print('chest')
if l > c and l > f:
	print('biceps')
if f > c and f > l:
	print('back')


n = int(input())
m = map(int, input().split())
chest = 0
biceps = 0
back = 0
ind = 0
for k in m:
	if ind % 3 == 0:
		chest += k
	elif ind % 3 == 1:
		biceps += k
	else:
		back += k
	ind += 1
maxe = max(chest, biceps, back)
if maxe == chest:
	print('chest')
elif maxe == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
s = list(map(int, input().split()))
flag = 1
kol1 = 0
kol2 = 0
kol3 = 0
for i in range(n):
	if flag == 1:
		kol1 += s[i]
	elif flag == 2:
		kol2 += s[i]
	else:
		kol3 += s[i]
		flag = 0
	flag += 1
if max(kol1, kol2, kol3) == kol1:
	print('chest')
elif max(kol1, kol2, kol3) == kol2:
	print('biceps')
else:
	print('back')


c = b = ba = 0
a = int(input())
l = list(map(int, input().split()))
for i in range(0, a):
	if i % 3 == 0:
		c += l[i]
	if i % 3 == 1:
		b += l[i]
	if i % 3 == 2:
		ba += l[i]
if c >= b and c >= ba:
	print('chest')
if ba >= c and ba >= b:
	print('back')
if b >= ba and b >= c:
	print('biceps')


n = int(input())
t = [int(x) for x in input().split()]
c = bi = ba = 0
for ii in range(n):
	if (ii + 1) % 3 == 1:
		c += t[ii]
	elif (ii + 1) % 3 == 2:
		bi += t[ii]
	else:
		ba += t[ii]
if c > bi and c > ba:
	print('chest')
elif bi > c and bi > ba:
	print('biceps')
else:
	print('back')


no = int(input())
x = list(map(int, input().split()))
chest = 0
bicep = 0
back = 0
for i in range(0, no, 3):
	chest += x[i]
for i in range(1, no, 3):
	bicep += x[i]
for i in range(2, no, 3):
	back += x[i]
if chest > bicep and chest > back:
	print('chest')
elif bicep > chest and bicep > back:
	print('biceps')
elif back > chest and back > bicep:
	print('back')


n = int(input())
a = list(map(int, input().split()))
m1 = sum(a[::3])
m2 = sum(a[1::3])
m3 = sum(a[2::3])
if m1 > m2 and m1 > m3:
	print('chest')
elif m2 > m1 and m2 > m3:
	print('biceps')
else:
	print('back')


n = int(input())
t = list(map(int, input().split()))
ti = len(t)
chest = 0
biceps = 0
back = 0
for i in range(ti):
	if i % 3 == 0:
		chest = chest + t[i]
	elif i % 3 == 1:
		biceps = biceps + t[i]
	elif i % 3 == 2:
		back = back + t[i]
if max(chest, biceps, back) == chest:
	print('chest')
elif max(chest, biceps, back) == biceps:
	print('biceps')
elif max(chest, biceps, back) == back:
	print('back')


def solve(test):
	ans = 1
	n = int(input())
	a = list(map(int, input().split()))
	cnt = [0 for i in range(3)]
	for i in range(n):
		cnt[i % 3] += a[i]
	print('chest' if cnt[0] > cnt[1] and cnt[0] > cnt[2] else 'biceps' if cnt[1] > cnt[2] else 'back')
t = 1
for _ in range(t):
	solve(_ + 1)


n = int(input())
arr = [int(i) for i in input().split()]
ans = [0, 0, 0]
an = ['chest', 'biceps', 'back']
for i in range(n):
	ans[i % 3] += arr[i]
print(an[ans.index(max(ans))])


a = int(input())
b = input()
b = b.split()
b = b[:a]
total = [0, 0, 0]
x = 0
for i in b:
	i = int(i)
	b[x] = i
	x += 1
q = 0
for j in range(len(b)):
	if q < len(b):
		total[0] = total[0] + b[q]
		q += 3
	else:
		break
w = 1
for j in range(len(b)):
	if w < len(b):
		total[1] = total[1] + b[w]
		w += 3
	else:
		break
e = 2
for j in range(len(b)):
	if e < len(b):
		total[2] = total[2] + b[e]
		e += 3
	else:
		break
if total[0] == max(total):
	print('chest')
elif total[1] == max(total):
	print('biceps')
elif total[2] == max(total):
	print('back')


input()
a = list(map(int, input().split()))
r = [0] * 3
for (i, x) in enumerate(a):
	r[i % 3] += x
print(('chest', 'biceps', 'back')[r.index(max(r))])


n = int(input())
a = list(map(int, input().split()))
d = {'chest': 0, 'biceps': 0, 'back': 0}
for i in range(n):
	if i % 3 == 0:
		d['chest'] += a[i]
	elif i % 3 == 1:
		d['biceps'] += a[i]
	else:
		d['back'] += a[i]
print(max(d, key=d.get))


n = int(input())
lis = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
for i in range(1, n + 1):
	if i % 3 == 1:
		chest += lis[i - 1]
	elif i % 3 == 2:
		biceps += lis[i - 1]
	else:
		back += lis[i - 1]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
elif back > chest and back > biceps:
	print('back')
else:
	print('ambiguous')


ch = 'chest'
bi = 'biceps'
ba = 'back'
m = {ch: 0, bi: 0, ba: 0}
n = int(input())
a = map(int, input().split())
s = [ch, bi, ba] * n
z = zip(s[:n], a)
for (e, ai) in z:
	m[e] += ai
print(max(m, key=m.get))


input()
a = list(map(int, input().split()))
d1 = {1: 'chest', 2: 'biceps', 0: 'back'}
d2 = {1: 0, 2: 0, 0: 0}
Max = 0
for i in range(len(a)):
	d2[(i + 1) % 3] += a[i]
	if d2[(i + 1) % 3] > d2[Max]:
		Max = (i + 1) % 3
print(d1[Max])


d = int(input())
e = [int(x) for x in input().split()]
(chest, biceps, back) = (0, 0, 0)
for i in range(0, d, 3):
	chest += e[i]
for i in range(1, d, 3):
	biceps += e[i]
for i in range(2, d, 3):
	back += e[i]
e = [chest, biceps, back]
if max(e) == chest:
	print('chest')
elif max(e) == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
a = input().split()
arr = [0, 0, 0]
e = ['back', 'chest', 'biceps']
for i in range(1, n + 1):
	arr[i % 3] += int(a[i - 1])
print(e[arr.index(max(arr))])


n = int(input())
a = [int(x) for x in input().split(' ')]
(c, bi, ba) = (0, 0, 0)
for i in range(len(a)):
	if i % 3 == 0:
		c += a[i]
	elif i % 3 == 1:
		bi += a[i]
	else:
		ba += a[i]
if c == max(c, bi, ba):
	print('chest')
elif bi == max(c, bi, ba):
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
ch = 0
bi = 0
ba = 0
for i in range(n):
	if i % 3 == 0:
		ch += a[i]
	elif i % 3 == 1:
		bi += a[i]
	elif i % 3 == 2:
		ba += a[i]
mx = max([ch, bi, ba])
if ch == mx:
	print('chest')
elif bi == mx:
	print('biceps')
elif ba == mx:
	print('back')


c = 0
b = 0
back = 0
x = int(input())
y = input().split(' ')
for i in range(len(y)):
	if i % 3 == 0:
		c = c + int(y[i])
	elif i % 3 == 1:
		b = b + int(y[i])
	elif i % 3 == 2:
		back = back + int(y[i])
if c > b and c > back:
	print('chest')
elif b > c and b > back:
	print('biceps')
else:
	print('back')


n = int(input())
x = list(map(int, input().split()))
ex = ['chest', 'biceps', 'back']
ca = [0, 0, 0]
for i in range(n):
	ca[i % 3] += x[i]
print(ex[ca.index(max(ca))])


n = int(input())
A = list(map(int, input().split()))
(sum, sum1, sum2, m) = (0, 0, 0, [])
if n >= 4:
	for i in range(0, len(A), 3):
		sum += A[i]
	for i in range(1, len(A), 3):
		sum1 += A[i]
	for i in range(2, len(A), 3):
		sum2 += A[i]
	m.append(sum)
	m.append(sum1)
	m.append(sum2)
	if m[0] > max(m[1], m[2]):
		print('chest')
	elif m[1] > max(m[0], m[2]):
		print('biceps')
	elif m[2] > max(m[0], m[1]):
		print('back')
elif n == 3:
	if A[0] > (A[1] and A[2]):
		print('chest')
	elif A[1] > (A[0] and A[2]):
		print('biceps')
	elif A[2] > (A[0] and A[1]):
		print('back')
elif n == 2:
	if A[0] < A[1]:
		print('biceps')
	else:
		print('chest')
elif n == 1:
	print('chest')


n = int(input())
a = list(map(int, input().split()))
(d, b, p) = (0, 0, 0)
for i in range(n):
	if i % 3 == 0:
		d += a[i]
	elif i % 3 == 1:
		b += a[i]
	elif i % 3 == 2:
		p += a[i]
if d > b and d > p:
	print('chest')
elif b > d and b > p:
	print('biceps')
elif p > d and p > b:
	print('back')


count1 = 0
count2 = 0
count3 = 0
v1 = 0
v2 = 1
z = int(input())
x = list(map(int, input().split()))
for c in range(z):
	if c == v1:
		count1 += x[c]
		v1 += 3
	elif c == v2:
		count2 += x[c]
		v2 += 3
	else:
		count3 += x[c]
if count1 > count2 and count1 > count3:
	print('chest')
elif count2 > count1 and count2 > count3:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
i = 0
sums_1 = 0
while i < n:
	sums_1 += a[i]
	i += 3
i = 1
sums_2 = 0
while i < n:
	sums_2 += a[i]
	i += 3
i = 2
sums_3 = 0
while i < n:
	sums_3 += a[i]
	i += 3
if sums_1 == max(sums_1, sums_2, sums_3):
	print('chest')
elif sums_2 == max(sums_1, sums_2, sums_3):
	print('biceps')
else:
	print('back')


a = int(input())
b = list(map(int, input().split()))
c = [0, 0, 0]
for i in range(len(b)):
	c[i % 3] += b[i]
d = c.index(max(c))
if d == 0:
	print('chest')
elif d == 1:
	print('biceps')
else:
	print('back')


n = int(input())
a = [int(i) for i in input().split()]
b = 3 * [0]
d = ['chest', 'biceps', 'back']
for i in range(n):
	b[i % 3] += a[i]
z = b.index(max(b))
print(d[z])


n = int(input())
inputlists = list(map(int, input().strip().split()))
lists = [0, 0, 0]
for i in range(n):
	lists[i % 3] += inputlists[i]
max_ex = max(lists)
if max_ex == lists[0]:
	print('chest', end='')
elif max_ex == lists[1]:
	print('biceps', end='')
elif max_ex == lists[2]:
	print('back', end='')


n = int(input())
a = list(map(int, input().split()))
muscles = [0, 0, 0]
answer = ['chest', 'biceps', 'back']
muscles[0] = sum(a[::3])
muscles[1] = sum(a[1::3])
muscles[2] = sum(a[2::3])
strongest = muscles.index(max(muscles))
print(answer[strongest])


pairs = {'chest': 0, 'biceps': 0, 'back': 0}
n = int(input())
arr = list(map(int, input().split(' ')[:n]))
for i in range(n):
	if i % 3 == 0:
		pairs['chest'] = int(pairs['chest']) + arr[i]
		continue
	if i % 3 == 1:
		pairs['biceps'] = int(pairs['biceps']) + arr[i]
		continue
	else:
		pairs['back'] = int(pairs['back']) + arr[i]
		continue
if pairs['chest'] > pairs['biceps'] and pairs['chest'] > pairs['back']:
	print('chest')
	exit()
if pairs['biceps'] > pairs['chest'] and pairs['biceps'] > pairs['back']:
	print('biceps')
else:
	print('back')


k = int(input())
s = list(map(int, input().split()))
if k == 1:
	print('chest')
elif k == 2:
	if s[0] > s[1]:
		print('chest')
	else:
		print('biceps')
elif k == 3:
	if s[0] > s[1]:
		if s[0] > s[2]:
			print('chest')
		else:
			print('back')
	elif s[1] > s[2]:
		print('biceps')
	else:
		print('back')
elif k > 3:
	z = k % 3
	l = len(s)
	c = 0
	p = 0
	b = 0
	for q in range(0, l - z, 3):
		c = c + s[q]
		p = p + s[q + 1]
		b = b + s[q + 2]
	if z == 2:
		c = c + s[l - 2]
		p = p + s[l - 1]
	elif z == 1:
		c = c + s[l - 1]
	if c > p:
		if c > b:
			print('chest')
		else:
			print('back')
	elif p > b:
		print('biceps')
	else:
		print('back')


x = int(input())
S = [0, 0, 0]
L = list(map(int, input().split()))
for i in range(x):
	if i % 3 == 0:
		S[0] += L[i]
	if i % 3 == 1:
		S[1] += L[i]
	if i % 3 == 2:
		S[2] += L[i]
index = S.index(max(S))
if index == 0:
	print('chest')
if index == 1:
	print('biceps')
if index == 2:
	print('back')


n = int(input())
array = list(map(int, input().split()))
a = 0
b = 0
c = 0
for i in range(0, n, 3):
	a += array[i]
for i in range(1, n, 3):
	b += array[i]
for i in range(2, n, 3):
	c += array[i]
if a > b and a > c:
	print('chest')
if b > a and b > c:
	print('biceps')
if c > a and c > b:
	print('back')


n = int(input())
arr = list(map(int, input().split(' ')))
ex = [0] * 3
for i in range(0, len(arr)):
	ex[i % 3] += arr[i]
exc = ex.index(max(ex))
if exc == 0:
	print('chest')
elif exc == 1:
	print('biceps')
elif exc == 2:
	print('back')


n = int(input())
a = [int(x) for x in input().split()]
(chest, biceps, back) = (0, 0, 0)
count = 0
for i in range(1, n + 1):
	count += 1
	if count % 3 == 0:
		back += a[i - 1]
		count = 0
	elif count % 2 == 0:
		biceps += a[i - 1]
	else:
		chest += a[i - 1]
dic = dict({'chest': chest, 'biceps': biceps, 'back': back})
print(max(dic, key=dic.get))


n = int(input())
a = list(map(int, input().split())) + [0] * 3
s = [sum(a[x::3]) for x in range(3)]
if s[0] > s[1] and s[0] > s[2]:
	print('chest')
elif s[1] > s[0] and s[1] > s[2]:
	print('biceps')
else:
	print('back')


n = int(input())
mat = list(map(int, input().split()))
exe = ['chest', 'biceps', 'back']
arr = [0, 0, 0]
i = 0
while n > 0:
	n -= 3
	try:
		arr[i % 3] += mat[i]
		arr[(i + 1) % 3] += mat[i + 1]
		arr[(i + 2) % 3] += mat[i + 2]
	except:
		break
	i += 3
ind = arr.index(max(arr))
print(exe[ind])


n = int(input())
l_n = list(map(int, input().split()))
a_t = [0] * 3
for i in range(n):
	a_t[i % 3] += l_n[i]
if a_t[0] > a_t[1] and a_t[0] > a_t[2]:
	print('chest')
elif a_t[1] > a_t[2]:
	print('biceps')
else:
	print('back')


k = int(input())
a = list(map(int, input().split()))
(c, d, e) = (0, 0, 0)
for i in range(len(a)):
	if i % 3 == 0:
		c += a[i]
	elif i % 3 == 1:
		d += a[i]
	elif i % 3 == 2:
		e += a[i]
if c > d and c > e:
	print('chest')
elif d > c and d > e:
	print('biceps')
else:
	print('back')


def solve(arr):
	biceps = 0
	chest = 0
	back = 0
	for i in range(0, len(arr), 3):
		chest += arr[i]
		if i + 1 <= len(arr) - 1:
			biceps += arr[i + 1]
		if i + 2 <= len(arr) - 1:
			back += arr[i + 2]
	max_el = max(biceps, chest, back)
	if max_el == biceps:
		return 'biceps'
	if max_el == chest:
		return 'chest'
	if max_el == back:
		return 'back'

def main():
	n = int(input())
	arr = list(map(int, input().split(' ')))
	print(solve(arr))
main()


t = input()
li = [int(x) for x in input().split()]
li2 = [sum(li[i::3]) for i in range(3)]
ind = ['chest', 'biceps', 'back']
print(ind[li2.index(max(li2))])


n = int(input())
nl = list(map(int, input().split()))
(c, bi, ba) = (0, 0, 0)
for i in range(n):
	j = i % 3
	if j == 0:
		c += nl[i]
	elif j == 1:
		bi += nl[i]
	elif j == 2:
		ba += nl[i]
ans = max(c, bi, ba)
if ans == c:
	print('chest')
elif ans == bi:
	print('biceps')
else:
	print('back')


n = int(input())
arr = [int(i) for i in input().split(' ')]
(a, b, c) = (0, 0, 0)
for i in range(1, n + 1):
	if i % 3 == 0:
		a += arr[i - 1]
	if i % 3 == 1:
		b += arr[i - 1]
	if i % 3 == 2:
		c += arr[i - 1]
maxi = max(a, b, c)
print('back' if maxi == a else 'chest' if maxi == b else 'biceps')


N = int(input())
A = list(map(int, input().split()))
xs = [0, 0, 0]
for (i, a) in enumerate(A):
	xs[i % 3] += a
maxx = max(xs)
l = ['chest', 'biceps', 'back']
for i in range(3):
	if xs[i] == maxx:
		print(l[i])
		exit()


n = int(input())
(c, bi, b) = (0, 0, 0)
x = list(map(int, input().split()))
result = {}
counter = 1
for i in x:
	if counter in result.keys():
		result[counter] += i
	else:
		result[counter] = i
	counter += 1
	if counter > 3:
		counter = 1
l = max(result.values())
if result[1] == l:
	print('chest')
elif result[2] == l:
	print('biceps')
else:
	print('back')


i = int(input())
a = list(map(int, input().split()))
(b, c, k) = (0, 0, 0)
for _ in range(i):
	if _ % 3 == 0:
		b += a[_]
	elif _ % 3 == 1:
		c += a[_]
	elif _ % 3 == 2:
		k += a[_]
if b == max(b, c, k):
	print('chest')
elif c == max(b, c, k):
	print('biceps')
elif k == max(b, c, k):
	print('back')


n = int(input())
a = list(map(int, input().split()))
chest = sum(a[0::3])
biceps = sum(a[1::3])
back = sum(a[2::3])
if chest == max(chest, biceps, back):
	i = 0
elif biceps == max(chest, biceps, back):
	i = 1
else:
	i = 2
print(['chest', 'biceps', 'back'][i])


n = int(input())
l = list(map(int, input().split()))[:n]
chest = 0
biceps = 0
back = 0
a = 0
b = 1
c = 2
for i in range(len(l)):
	if a < len(l):
		chest = chest + l[a]
	else:
		break
	if b < len(l):
		biceps = biceps + l[b]
	else:
		break
	if c < len(l):
		back = back + l[c]
	else:
		break
	a = a + 3
	b = b + 3
	c = c + 3
f = max(chest, biceps)
d = max(f, back)
if d == chest:
	print('chest')
elif d == biceps:
	print('biceps')
else:
	print('back')


input()
tmp = list(map(int, input().split()))
C = [0, 0, 0]
i = 0
for _ in tmp:
	C[i] += _
	i += 1
	if i == 3:
		i = 0
print(['chest', 'biceps', 'back'][C.index(max(C))])


n = int(input())
a = list(map(int, input().split()))[:n]
ch = sum(a[0::3])
bc = sum(a[1::3])
bk = sum(a[2::3])
max = 'chest'
if bc > ch and bc > bk:
	max = 'biceps'
elif bk > ch and bk > bc:
	max = 'back'
print(max)


from sys import stdin, stdout
st = lambda : list(stdin.readline().strip())
li = lambda : list(map(int, stdin.readline().split()))
mp = lambda : map(int, stdin.readline().split())
inp = lambda : int(stdin.readline())
pr = lambda n: stdout.write(str(n) + '\n')
mod = 1000000007
n = inp()
l = li()
(c, b, bi) = (0, 0, 0)
for i in range(n):
	if i % 3 == 0:
		c += l[i]
	elif i % 3 == 1:
		bi += l[i]
	else:
		b += l[i]
x = max(c, b, bi)
if x == c:
	print('chest')
elif x == b:
	pr('back')
else:
	print('biceps')


n = int(input())
l1 = list(map(int, input().split()))
(a1, a2, a3) = (0, 0, 0)
for i in range(n):
	if i % 3 == 0:
		a1 += l1[i]
	elif i % 3 == 1:
		a2 += l1[i]
	else:
		a3 += l1[i]
if a1 == max(a1, a2, a3):
	print('chest')
elif a2 == max(a1, a2, a3):
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
l1 = []
l2 = []
l3 = []
i = 0
while i <= len(a):
	if i == len(a):
		break
	else:
		l1.append(a[i])
	if i == len(a):
		break
	else:
		i += 1
	if i == len(a):
		break
	else:
		l2.append(a[i])
		i += 1
	if i == len(a):
		break
	else:
		l3.append(a[i])
		i += 1
a1 = sum(l1)
a2 = sum(l2)
a3 = sum(l3)
k = max(sum(l1), sum(l2), sum(l3))
if a1 == k:
	print('chest')
elif a2 == k:
	print('biceps')
else:
	print('back')


n = int(input())
workout_plan = list(map(int, input().split()))
(repeat_chest, repeat_biceps, repeat_back) = (0, 0, 0)
for i in range(n):
	if i % 3 == 0:
		repeat_chest += workout_plan[i]
	elif i % 3 == 1:
		repeat_biceps += workout_plan[i]
	else:
		repeat_back += workout_plan[i]
if repeat_chest > repeat_biceps and repeat_chest > repeat_back:
	print('chest')
elif repeat_biceps > repeat_chest and repeat_biceps > repeat_back:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
ch = 0
bi = 0
ba = 0
h = 0
for f in range(n):
	h += 1
	if h == 4:
		h = 1
	if h == 1:
		ch += l[f]
	elif h == 2:
		bi += l[f]
	else:
		ba += l[f]
if ch > bi and ch > ba:
	print('chest')
elif bi > ch and bi > ba:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
sum1 = 0
sum2 = 0
sum3 = 0
for i in range(n):
	if i % 3 == 0:
		sum1 += a[i]
	if i % 3 == 1:
		sum2 += a[i]
	if i % 3 == 2:
		sum3 += a[i]
if max(sum1, sum2, sum3) == sum1:
	print('chest')
if max(sum1, sum2, sum3) == sum2:
	print('biceps')
if max(sum1, sum2, sum3) == sum3:
	print('back')


from collections import defaultdict

def solution():
	n = int(input())
	arr = [int(x) for x in input().split(' ')]
	t = ['chest', 'biceps', 'back']
	i = 0
	d = defaultdict(int)
	for x in arr:
		if i == 3:
			i = 0
		d[t[i]] += x
		i += 1
	print(max(d, key=lambda x: d[x]))
solution()


N = int(input())
num = [int(i) for i in input().split()]
pro = 0
chest = 0
biceps = 0
back = 0
for i in range(N):
	if pro == 0:
		chest += num[i]
		pro += 1
	elif pro == 1:
		biceps += num[i]
		pro += 1
	elif pro == 2:
		back += num[i]
		pro = 0
if chest > biceps and chest > back:
	print('chest')
if chest < biceps and back < biceps:
	print('biceps')
if chest < back and biceps < back:
	print('back')


import math, string, itertools, fractions, heapq, collections, re, array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10 ** 7)
inf = 10 ** 20
eps = 1.0 / 10 ** 10
mod = 10 ** 9 + 7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]

def LI():
	return [int(x) for x in sys.stdin.readline().split()]

def LI_():
	return [int(x) - 1 for x in sys.stdin.readline().split()]

def LF():
	return [float(x) for x in sys.stdin.readline().split()]

def LS():
	return sys.stdin.readline().split()

def I():
	return int(sys.stdin.readline())

def F():
	return float(sys.stdin.readline())

def S():
	return input()

def pf(s):
	return print(s, flush=True)

def main():
	n = I()
	a = LI()
	t = ['chest', 'biceps', 'back']
	c = [0] * 3
	for i in range(n):
		c[i % 3] += a[i]
	return t[c.index(max(c))]
print(main())


n = int(input())
string = input()
numbers = string.split(' ')
for x in range(n):
	numbers[x] = int(numbers[x])
exercises = [0, 0, 0]
for x in range(3):
	y = x
	exercises[x] = 0
	while y < n:
		exercises[x] += numbers[y]
		y += 3
muscles = ['chest', 'biceps', 'back']
print(muscles[exercises.index(max(exercises))])


n = int(input())
a = list(map(int, input().split()))
j = 0
chest = 0
biceps = 0
back = 0
for i in range(n):
	if j == 0:
		chest = chest + a[i]
		j = 1
	elif j == 1:
		biceps = biceps + a[i]
		j = 2
	else:
		back = back + a[i]
		j = 0
if chest > biceps and chest > back:
	print('chest')
elif back > biceps and back > chest:
	print('back')
else:
	print('biceps')


n = int(input())
l = list(map(int, input().split()))
s = 0
t = 0
p = 0
m = []
for i in l[0:n:3]:
	s = s + i
m.append(s)
for i in l[1:n:3]:
	t = t + i
m.append(t)
for i in l[2:n:3]:
	p = p + i
m.append(p)
x = m.index(max(m))
if x == 0:
	print('chest')
elif x == 1:
	print('biceps')
elif x == 2:
	print('back')


x = int(input())
y = input().split()
p = []
q = []
r = []
for i in range(0, x, 3):
	p.append(int(y[i]))
	i = i + 3
for j in range(1, x, 3):
	q.append(int(y[j]))
	j = j + 3
for k in range(2, x, 3):
	r.append(int(y[k]))
	k = k + 3
a = sum(p)
b = sum(q)
c = sum(r)
if a > b and a > c:
	print('chest')
elif b > a and b > c:
	print('biceps')
elif c > a and c > b:
	print('back')


n = int(input())
f = [int(x) for x in input().split()]
g = {'chest': 0, 'biceps': 0, 'back': 0}
for j in range(0, int(n / 3)):
	g['chest'] += f[j * 3]
	g['biceps'] += f[j * 3 + 1]
	g['back'] += f[j * 3 + 2]
i = int(n / 3) * 3
if i < n:
	g['chest'] += f[i]
	i += 1
if i < n:
	g['biceps'] += f[i]
	i += 1
for (x, y) in g.items():
	if g[x] == max(g.values()):
		print(x)
		break


n = int(input())
L = [int(x) for x in input().split()]
c = [0, 0, 0]
for i in range(n):
	c[i % 3] += L[i]
if c[0] == max(c):
	print('chest')
if c[1] == max(c):
	print('biceps')
if c[2] == max(c):
	print('back')


c = input()
arr = [0, 0, 0]
inp = input()
inp = inp.split()
C = int(c)
v = 0
for i in range(C):
	if v == 3:
		v = 0
	if v == 0:
		arr[0] += int(inp[i])
	elif v == 1:
		arr[1] += int(inp[i])
	elif v == 2:
		arr[2] += int(inp[i])
	v += 1
m = max(arr[0], max(arr[1], arr[2]))
if m == arr[0]:
	print('chest')
elif m == arr[1]:
	print('biceps')
else:
	print('back')


x = input()
inp = input().split(' ')
chest = 0
back = 2
biceps = 1
count = [0, 0, 0]
for i in range(len(inp)):
	if i == chest:
		count[0] += int(inp[chest])
		chest += 3
	if i == biceps:
		count[1] += int(inp[biceps])
		biceps += 3
	if i == back:
		count[2] += int(inp[back])
		back += 3
maxVal = max(count)
if count[0] == maxVal:
	print('chest')
elif count[1] == maxVal:
	print('biceps')
else:
	print('back')


n = int(input())
k = 0
l = 0
m = 0
a = [int(x) for x in input().split()]
for i in range(len(a)):
	if (i + 1) % 3 == 1:
		k += a[i]
	if (i + 1) % 3 == 2:
		l += a[i]
	if (i + 1) % 3 == 0:
		m += a[i]
if max(k, l, m) == k:
	print('chest')
elif max(k, l, m) == l:
	print('biceps')
elif max(k, l, m) == m:
	print('back')


a = int(input())
b = list(map(int, input().split()))
ba = bi = c = x = int(0)
for x in range(a):
	if x % 3 == 0:
		c = c + b[x]
	elif x % 3 == 1:
		bi = bi + b[x]
	else:
		ba = ba + b[x]
if ba > bi and ba > c:
	print('back')
elif bi > ba and bi > c:
	print('biceps')
else:
	print('chest')


n = int(input())
A = [*map(int, input().split())]
(c, bi, ba) = (0, 0, 0)
for i in range(len(A)):
	if i % 3 == 0:
		c += A[i % n]
	elif i % 3 == 1:
		bi += A[i % n]
	elif i % 3 == 2:
		ba += A[i % n]
if c > bi and c > ba:
	print('chest')
elif bi > c and bi > ba:
	print('biceps')
elif ba > c and ba > bi:
	print('back')


n = int(input())
l = list(map(int, input().split()))
S1 = l[0::3]
S2 = l[1::3]
S3 = l[2::3]
s1 = sum(S1)
s2 = sum(S2)
s3 = sum(S3)
if s1 > s2 and s1 > s3:
	print('chest')
elif s2 > s1 and s2 > s3:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
count_chest = 0
count_biceps = 0
count_back = 0
for i in range(n):
	if i % 3 == 0:
		count_chest += a[i]
	elif i % 3 == 1:
		count_biceps += a[i]
	elif i % 3 == 2:
		count_back += a[i]
	else:
		print('что то не так')
if count_chest > count_biceps and count_chest > count_back:
	print('chest')
elif count_biceps > count_chest and count_biceps > count_back:
	print('biceps')
elif count_back > count_chest and count_back > count_biceps:
	print('back')
else:
	print('сбой снова')


n = int(input())
l = list(map(int, input().split()))
d = {}
d['chest'] = 0
d['biceps'] = 0
d['back'] = 0
for i in range(n):
	if i % 3 == 0:
		d['chest'] += l[i]
	elif i % 3 == 1:
		d['biceps'] += l[i]
	else:
		d['back'] += l[i]
e = max(d.values())
for i in d:
	if d[i] == e:
		print(i)
		break


a = int(input())
b = list(map(int, input().split()))
back = sum(b[2::3])
chest = sum(b[::3])
bic = sum(b[1::3])
c = max(back, chest, bic)
if back == c:
	print('back')
elif chest == c:
	print('chest')
else:
	print('biceps')


a = int(input())
b = list(map(int, input().split()))
chest = 0
bic = 0
esp1 = 0
otros = []
i = 1
for num in b:
	if i % 3 == 0:
		esp1 = esp1 + num
	else:
		otros.append(num)
	i += 1
j = 1
for num2 in otros:
	if j % 2 == 0:
		bic = bic + num2
	else:
		chest = chest + num2
	j += 1
if chest > bic and chest > esp1:
	print('chest')
elif bic > chest and bic > esp1:
	print('biceps')
else:
	print('back')


n = int(input())
seq = list(map(int, input().split()))
rs = [0, 0, 0]
for i in range(n):
	rs[i % 3] += seq[i]
index = rs.index(max(rs))
if index == 0:
	print('chest')
elif index == 1:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
sum1 = 0
sum2 = 0
sum3 = 0
list1 = []
if len(a) == 1:
	print('chest')
elif len(a) == 2:
	if a[0] > a[1]:
		print('chest')
	else:
		print('biceps')
else:
	count = 0
	for i in a:
		count += 1
		if count % 3 == 0:
			sum3 += i
		elif (count - 1) % 3 != 0:
			sum2 += i
		else:
			sum1 += i
	if sum1 > sum2 and sum1 > sum3:
		print('chest')
	elif sum2 > sum3 and sum2 > sum1:
		print('biceps')
	else:
		print('back')


n = int(input())
j = n + 1
a = [0] * n
a = list(map(int, input().split()))
bi = 0
ba = 0
ch = 0
if n == 1:
	ch = ch + a[0]
elif n == 2:
	ch = ch + a[0]
	bi = bi + a[1]
else:
	j = 0
	for i in range(0, int(n / 3)):
		ch = ch + a[j]
		bi = bi + a[j + 1]
		ba = ba + a[j + 2]
		j = j + 3
	t = n % 3
	if t == 1:
		ch = ch + a[n - t]
	elif t == 2:
		ch = ch + a[n - t]
		bi = bi + a[n - t + 1]
if ch >= bi:
	if ch >= ba:
		print('chest')
	else:
		print('back')
elif bi >= ba:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
s1 = [l[i] for i in range(0, n, 3)]
s2 = [l[i] for i in range(1, n, 3)]
s3 = [l[i] for i in range(2, n, 3)]
su1 = sum(s1)
su2 = sum(s2)
su3 = sum(s3)
if max(su1, su2, su3) == su1:
	print('chest')
elif max(su1, su2, su3) == su2:
	print('biceps')
else:
	print('back')


def check(l):
	chest = 0
	biceps = 0
	back = 0
	for i in range(0, 2):
		if len(l) % 3 == 0:
			break
		l.append(0)
	for i in range(0, len(l), 3):
		chest += l[i]
		biceps += l[i + 1]
		back += l[i + 2]
	if chest > biceps and chest > back:
		return 'chest'
	elif biceps > chest and biceps > back:
		return 'biceps'
	else:
		return 'back'
t = int(input())
a = input().split()
b = map(int, a)
i_list = list(b)
print(check(i_list))


n = int(input())
a = list(map(int, input().split()))
x = sum(a[::3])
y = sum(a[1::3])
z = sum(a[2::3])
if x > y and x > z:
	print('chest')
elif y > x and y > z:
	print('biceps')
else:
	print('back')


n = int(input())
out = [0] * 3
arr = list(map(int, input().split()))
for i in range(n):
	out[i % 3] += arr[i]
a = ['chest', 'biceps', 'back']
print(a[out.index(max(out))])


import math, string, itertools, fractions, heapq, collections, re, array, bisect, sys, random, time, queue, copy
sys.setrecursionlimit(10 ** 7)
inf = 10 ** 20
mod = 10 ** 9 + 7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]

def LI():
	return [int(x) for x in sys.stdin.readline().split()]

def LI_():
	return [int(x) - 1 for x in sys.stdin.readline().split()]

def I():
	return int(sys.stdin.readline())

def LS():
	return sys.stdin.readline().split()

def S():
	return input()

def main():
	a = b = c = 0
	n = I()
	l = LI()
	for (i, x) in enumerate(l):
		if i % 3 == 0:
			a += x
		elif i % 3 == 1:
			b += x
		else:
			c += x
	l2 = sorted([a, b, c], reverse=True)
	if l2[0] == a:
		return 'chest'
	elif l2[0] == b:
		return 'biceps'
	else:
		return 'back'
print(main())


n = int(input())
a = [int(i) for i in input().split()]
chest = 0
bicep = 0
back = 0
for i in range(len(a)):
	if i % 3 == 0:
		chest += a[i]
	if i % 3 == 1:
		bicep += a[i]
	if i % 3 == 2:
		back += a[i]
p = max(chest, bicep, back)
if chest == p:
	print('chest')
elif bicep == p:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
(c, bi, b) = (0, 0, 0)
if len(a) == 2:
	c += a[0]
	bi += a[1]
elif len(a) == 1:
	c += a[0]
elif len(a) >= 3:
	for i in range(0, n, 3):
		c += a[i]
	for j in range(1, n, 3):
		bi += a[j]
	for k in range(2, n, 3):
		b += a[k]
if c > bi and c > b:
	print('chest')
elif bi > c and bi > b:
	print('biceps')
elif b > c and b > bi:
	print('back')


n = int(input())
a = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
for i in range(n):
	if i == 0 or i == 3 or i == 6 or (i == 9) or (i == 12) or (i == 15) or (i == 18):
		chest = chest + a[i]
	elif i == 1 or i == 4 or i == 7 or (i == 10) or (i == 13) or (i == 16) or (i == 19):
		biceps = biceps + a[i]
	else:
		back = back + a[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
s = ['c', 'bi', 'ba']
d = {}
ans = [0, 0, 0]
for (ind, i) in enumerate(map(int, input().split())):
	d.setdefault(s[ind % 3], [0])[0] += i
for i in d:
	if i == 'c':
		ans[0] = d[i][0]
	elif i == 'bi':
		ans[1] = d[i][0]
	else:
		ans[2] = d[i][0]
if ans[0] > ans[1] and ans[0] > ans[2]:
	print('chest')
elif ans[1] > ans[0] and ans[1] > ans[2]:
	print('biceps')
else:
	print('back')


def greg_workout(a):
	sum_1 = 0
	sum_2 = 0
	sum_3 = 0
	for i in range(0, len(a), 3):
		sum_1 = sum_1 + a[i]
	for i in range(1, len(a), 3):
		sum_2 = sum_2 + a[i]
	for i in range(2, len(a), 3):
		sum_3 = sum_3 + a[i]
	maxi = max(sum_1, sum_2, sum_3)
	if maxi == sum_1:
		print('chest')
	elif maxi == sum_2:
		print('biceps')
	else:
		print('back')
n = int(input(''))
a = list(map(int, input('').split()))
greg_workout(a)


n = int(input())
li = list((int(num) for num in input().strip().split()))[:n]
ch = bi = ba = 0
for i in range(0, n, 3):
	ch += li[i]
for i in range(1, n, 3):
	bi += li[i]
for i in range(2, n, 3):
	ba += li[i]
di = {ch: 'chest', bi: 'biceps', ba: 'back'}
print(di[max(di.keys())])


n = int(input())
exc = list(map(int, input().split()))
count_chest = 0
count_biceps = 0
count_back = 0
for i in range(1, n + 1):
	if i % 3 == 0:
		count_back += exc[i - 1]
	if i % 3 == 1:
		count_chest += exc[i - 1]
	if i % 3 == 2:
		count_biceps += exc[i - 1]
max_count = max(count_chest, count_back, count_biceps)
if count_chest == max_count:
	print('chest')
elif count_biceps == max_count:
	print('biceps')
else:
	print('back')


n = int(input())
training = list(map(int, input().split()))
b = [0] * 3
t1 = ['chest', 'biceps', 'back']
for i in range(n):
	b[i % 3] += training[i]
t2 = b.index(max(b))
print(t1[t2])


try:
	t = int(input())
	s = [int(i) for i in input().split()]
	chest = 0
	biceps = 0
	back = 0
	c = []
	bi = []
	ba = []
	all = []
	for i in range(t):
		if i % 3 == 0:
			c.append(s[i])
		if i % 3 == 1:
			bi.append(s[i])
		if i % 3 == 2:
			ba.append(s[i])
	all.append(sum(c))
	all.append(sum(bi))
	all.append(sum(ba))
	k = all.index(max(all))
	if k == 0:
		print('chest')
	if k == 1:
		print('biceps')
	if k == 2:
		print('back')
except:
	pass


n = int(input())
a = [int(s) for s in input().split(' ')]
c = sum([a[i] for i in range(0, n, 3)])
bi = sum([a[i] for i in range(1, n, 3)])
ba = sum([a[i] for i in range(2, n, 3)])
if max([c, bi, ba]) == c:
	print('chest')
elif max([c, bi, ba]) == bi:
	print('biceps')
else:
	print('back')


import math
A = int(input())
a = ()
a = list(map(int, input().split()))
biceps = 0
back = 0
chest = 0
for i in range(A):
	if math.fmod(i, 3) == 1:
		biceps = biceps + a[i]
	elif math.fmod(i, 3) == 2:
		back = back + a[i]
	elif math.fmod(i, 3) == 0:
		chest = chest + a[i]
if max(biceps, back, chest) == biceps:
	print('biceps')
elif max(biceps, back, chest) == back:
	print('back')
elif max(biceps, back, chest) == chest:
	print('chest')


n = int(input())
podhod = list(map(int, input('').split()))
(chest, biceps, back) = (0, 0, 0)
for i in range(len(podhod)):
	wrewer = (i + 1) % 3
	if (i + 1) % 3 == 1:
		chest += podhod[i]
	elif (i + 1) % 3 == 2:
		biceps += podhod[i]
	elif (i + 1) % 3 == 0:
		back += podhod[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
elif back > chest and back > biceps:
	print('back')


n = input()
list1 = list(map(int, input().split()))
k = 0
i1 = i2 = i3 = 0
while len(list1) % 3 != 0:
	list1.append(0)
llen = len(list1)
while llen > 0:
	i1 += list1[k]
	i2 += list1[k + 1]
	i3 += list1[k + 2]
	k += 3
	llen -= 3
(k1, k2, k3) = (i1, i2, i3)
if k1 > k2 and k1 > k3:
	print('chest')
elif k2 > k1 and k2 > k3:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
tr = [0] * 3
for i in range(n):
	tr[i % 3] += a[i]
m = max(tr)
if m == tr[0]:
	print('chest')
elif m == tr[1]:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
ch = sum(l[::3])
bi = sum(l[1::3])
ba = sum(l[2::3])
if ch > bi and ch > ba:
	print('chest')
elif bi > ba and bi > ch:
	print('biceps')
else:
	print('back')


variant = int(input())
biceps = chest = back = 0
A = list(map(int, input().split()))
for i in range(variant):
	i += 1
	if i % 3 == 1:
		chest += A[i - 1]
	elif i % 3 == 2:
		biceps += A[i - 1]
	else:
		back += A[i - 1]
if chest > biceps:
	if chest > back:
		print('chest')
	else:
		print('back')
elif biceps > back:
	print('biceps')
else:
	print('back')


from math import ceil, log, floor, sqrt
import math
k = 1

def mod_expo(n, p, m):
	result = 1
	while p != 0:
		if p % 2 == 1:
			result = result * n % m
		p //= 2
		n = n * n % m
	return result

def is_prime(n):
	m = 2
	while m * m <= n:
		if n % m == 0:
			return False
		m += 1
	return True

def find_sum(n, a):
	a.insert(0, 0)
	for i in range(1, n + 1):
		prev = a[i] & a[i - 1]
		cur = a[i] | a[i - 1]
		a[i - 1] = prev
		a[i] = cur
	return sum((m * m for m in a))

def prin_abc(x, y, z):
	l = [x, y, z]
	l.sort()
	if l[1] < l[2]:
		print('NO')
		return
	a = b = l[0]
	c = l[2]
	print('YES')
	print(a, b, c)

def get_scores(n, vals):
	l = 0
	r = n - 1
	turn = 0
	sereja = 0
	dima = 0
	while l <= r:
		if vals[l] > vals[r]:
			cur = vals[l]
			l += 1
		else:
			cur = vals[r]
			r -= 1
		if turn == 0:
			sereja += cur
		else:
			dima += cur
		turn = not turn
	print(sereja, dima)

def count_lamps(n, m):
	return (n * m + 1) // 2

def find_holidays(n):
	cnt = 2 * (n // 7)
	rem = n % 7
	mx = mn = cnt
	if rem == 1:
		mx += 1
	elif rem > 1:
		mx += 2
	if rem == 6:
		mn += 1
	print(mn, mx)

def count_eggs(n, s, t):
	return max(1, max(n - s + 1, n - t + 1))

def find_best(n, a):
	chest = 0
	biceps = 0
	back = 0
	for i in range(n):
		if i % 3 == 0:
			chest += a[i]
		elif i % 3 == 1:
			biceps += a[i]
		else:
			back += a[i]
	if chest > max(biceps, back):
		print('chest')
	elif biceps > max(chest, back):
		print('biceps')
	else:
		print('back')
t = 1
while t:
	t = t - 1
	(k, g) = (0, 0)
	points = []
	n = int(input())
	a = list(map(int, input().strip().split()))[:n]
	find_best(n, a)


n = int(input())
num = input()
a = []

def get_the_data(count, num, arr):
	for i in range(0, len(num)):
		if num[i] == ' ':
			arr.append(int(num[count:i]))
			count = i + 1
		elif i == len(num) - 1:
			arr.append(int(num[count:len(num)]))
	return arr
arr = get_the_data(0, num, a)
chest = 0
bicep = 0
back = 0
for i in range(0, len(arr), 3):
	chest += arr[i]
	if i + 1 <= len(arr) - 1:
		bicep += arr[i + 1]
	if i + 2 <= len(arr) - 1:
		back += arr[i + 2]
if chest > back and chest > bicep:
	print('chest')
elif bicep > chest and bicep > back:
	print('biceps')
else:
	print('back')


n = int(input())
chest = 0
biceps = 0
back = 0
A = input()
t = 0
for i in A.split():
	i = int(i)
	t = t + 1
	if t == 1:
		chest = chest + i
	elif t == 2:
		biceps = biceps + i
	elif t == 3:
		back = back + i
		t = 0
if chest == max(chest, biceps, back):
	print('chest')
elif biceps == max(chest, biceps, back):
	print('biceps')
elif back == max(chest, biceps, back):
	print('back')


input()
a = list(map(int, input().split()))
ch = 0
bi = 0
ba = 0
for i in range(0, len(a), 3):
	ch += a[i]
for j in range(1, len(a), 3):
	bi += a[j]
for k in range(2, len(a), 3):
	ba += a[k]
if max(ch, bi, ba) == ch:
	print('chest')
elif max(ch, bi, ba) == bi:
	print('biceps')
else:
	print('back')


import sys
input = sys.stdin.readline

def inp():
	return int(input())

def inlt():
	return list(map(int, input().split()))

def insr():
	s = input()
	return list(s[:len(s) - 1])

def invr():
	return map(int, input().split())
n = inp()
s = inlt()
i = 1
(chest, biceps, back) = (0, 0, 0)
for j in range(n):
	if i == 1:
		chest += s[j]
		i += 1
	elif i == 2:
		biceps += s[j]
		i += 1
	else:
		back += s[j]
		i = 1
w = max(chest, biceps, back)
if w == chest:
	print('chest')
elif w == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
cnt1 = 0
cnt2 = 0
cnt3 = 0
for i in range(0, n, 3):
	z = l[i:i + 3]
	if len(z) == 1:
		cnt1 += z[0]
	elif len(z) == 2:
		cnt1 += z[0]
		cnt2 += z[1]
	else:
		cnt1 += z[0]
		cnt2 += z[1]
		cnt3 += z[2]
if max(cnt1, cnt2, cnt3) == cnt1:
	print('chest')
elif max(cnt1, cnt2, cnt3) == cnt2:
	print('biceps')
else:
	print('back')


n = int(input())
A = list(map(int, input().split(' ')))
biceps = 0
back = 0
chest = 0
for i in range(0, n, 3):
	chest += A[i]
for j in range(1, n, 3):
	biceps += A[j]
for k in range(2, n, 3):
	back += A[k]
if max(chest, biceps, back) == chest:
	print('chest')
elif max(chest, biceps, back) == biceps:
	print('biceps')
else:
	print('back')


def solution():
	num = int(input())
	li = list(map(int, input().split()))
	chest = 0
	biceps = 0
	back = 0
	checker = []
	for i in range(num):
		if len(checker) == 0:
			chest += li[i]
			checker.append('c')
		elif checker[-1] == 'c':
			biceps += li[i]
			checker.append('b')
		elif checker[-1] == 'b':
			back += li[i]
			checker.append('ba')
		elif checker[-1] == 'ba':
			chest += li[i]
			checker.append('c')
	if chest > biceps and chest > back:
		return print('chest')
	elif biceps > chest and biceps > back:
		return print('biceps')
	else:
		return print('back')
solution()


n = int(input())
tokens = list(map(int, input().split()))
chest = 0
bicep = 0
back = 0
for (i, v) in enumerate(tokens):
	if i % 3 == 0:
		chest += v
	elif i % 3 == 1:
		bicep += v
	else:
		back += v
max_value = max(chest, bicep, back)
if max_value == chest:
	print('chest')
elif max_value == bicep:
	print('biceps')
else:
	print('back')


times = int(input())
inputArr = input().split(' ')
count = 1
totalBiceps = 0
totalChest = 0
totalBack = 0
for i in inputArr:
	i = int(i)
	if count == 1:
		totalChest += i
		count += 1
	elif count == 2:
		totalBiceps += i
		count += 1
	elif count == 3:
		totalBack += i
		count = 1
maximum = max(totalBiceps, totalChest, totalBack)
if maximum == totalChest:
	print('chest')
elif maximum == totalBiceps:
	print('biceps')
else:
	print('back')


import math
import collections
import bisect
import heapq
import time
import random
import itertools
import sys
N = int(input())
A = [int(x) for x in input().split()]
c = sum(A[::3] or [0])
b = sum(A[1::3] or [0])
p = sum(A[2::3] or [0])
m = max(c, b, p)
if m == c:
	print('chest')
elif m == b:
	print('biceps')
else:
	print('back')


n = int(input())
counts = [0, 0, 0]
names = ('chest', 'biceps', 'back')
for (i, v) in enumerate(map(int, input().split())):
	counts[i % 3] += v
print(max(zip(counts, names))[1])


n = int(input())
a = list(map(int, input().split()))
result = [0, 0, 0]
string = ['chest', 'biceps', 'back']
j = 0
for i in range(n):
	result[j % 3] += a[i]
	j += 1
print(string[result.index(max(result))])


n = int(input())
l = list(map(int, input().split()))
(ans1, ans2, ans3) = (0, 0, 0)
for i in range(0, n, 3):
	ans1 += l[i]
for i in range(1, n, 3):
	ans2 += l[i]
for i in range(2, n, 3):
	ans3 += l[i]
if ans1 > ans2 and ans1 > ans3:
	print('chest')
elif ans2 > ans1 and ans2 > ans3:
	print('biceps')
else:
	print('back')


mus = [0, 0, 0]
n = int(input())
ex = list(map(int, input().split()))
for i in range(n):
	mus[i % 3] += ex[i]
if mus[0] > mus[1]:
	if mus[0] > mus[2]:
		print('chest')
	else:
		print('back')
elif mus[1] > mus[2]:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(range(1, 26, 3))
b = list(range(2, 26, 3))
x = 0
li = list(map(int, input().split()))
d = e = f = 0
for i in range(n):
	if i in a:
		d += li[i]
	elif i in b:
		e += li[i]
	else:
		f += li[i]
y = max(d, e, f)
if y == d:
	print('biceps')
elif y == e:
	print('back')
else:
	print('chest')


n = int(input())
step = 0
m = [[]]
dic = {'chest': 0, 'back': 0, 'biceps': 0}
l = list(map(int, input().split()))
for i in l:
	if step == 3:
		step = 0
	if step == 0:
		dic['chest'] += i
	elif step == 1:
		dic['biceps'] += i
	elif step == 2:
		dic['back'] += i
	step += 1
max_key = max(dic, key=dic.get)
print(max_key)


ab = input()
array = list(map(int, input().split()))
c = bi = back = i = 0
while i < len(array):
	if i < len(array):
		c = c + array[i]
		i = i + 1
	if i < len(array):
		bi = bi + array[i]
		i = i + 1
	if i < len(array):
		back = back + array[i]
		i = i + 1
ans = max(c, bi, back)
if ans == c:
	print('chest')
if ans == bi:
	print('biceps')
if ans == back:
	print('back')


n = int(input())
l = list(map(int, input().split()))
count = [0] * 3
_max_idx = 0
for (i, v) in enumerate(l):
	idx = i % 3
	count[idx] += v
	if count[idx] > count[_max_idx]:
		_max_idx = idx
print(['chest', 'biceps', 'back'][_max_idx])


def solve(exercises):
	chest = sum(exercises[0::3])
	biceps = sum(exercises[1::3])
	back = sum(exercises[2::3])
	maxExercise = 'chest'
	if biceps > chest and biceps > back:
		maxExercise = 'biceps'
	elif back > chest and back > biceps:
		maxExercise = 'back'
	return maxExercise
n = int(input())
exercises = list(map(int, input().split(' ')))
print(solve(exercises))


n = int(input())
l = list(map(int, input().split()))
p = [0, 0, 0]
li = ['chest', 'biceps', 'back']
for i in range(1, n + 1):
	if i % 3 == 1:
		p[0] += l[i - 1]
	if i % 3 == 2:
		p[1] += l[i - 1]
	if i % 3 == 0:
		p[2] += l[i - 1]
print(li[p.index(max(p))])


n = int(input())
x = [int(x) for x in input().split()]
if n >= 3:
	chest = sum(x[0::3])
	bicep = sum(x[1::3])
	back = sum(x[2::3])
	if chest > bicep and chest > back:
		ans = 'chest'
	elif bicep > chest and bicep > back:
		ans = 'biceps'
	else:
		ans = 'back'
elif n == 1:
	ans = 'chest'
elif x[0] > x[1]:
	ans = 'chest'
else:
	ans = 'biceps'
print(ans)


n = int(input())
m = [0] * 3
k = 0
for i in [int(x) for x in input().split()]:
	m[k % 3] += i
	k += 1
if m[0] == max(m):
	print('chest')
elif m[1] == max(m):
	print('biceps')
else:
	print('back')


n = int(input())
k = list(map(int, input().split()))
(c, b, ba) = (0, 1, 2)
(s, bi, bc) = (0, 0, 0)
for i in range(n):
	if c >= n:
		break
	else:
		s += k[c]
		c += 3
for i in range(n):
	if b >= n:
		break
	else:
		bi += k[b]
		b += 3
for i in range(n):
	if ba >= n:
		break
	else:
		bc += k[ba]
		ba += 3
if s > bi and s > bc:
	print('chest')
elif bi > s and bi > bc:
	print('biceps')
else:
	print('back')


a = int(input())
k = [0, 0, 0]
p = 0
x = list(map(int, input().split()))
for i in range(a):
	if p == 3:
		p = 0
	k[p] += x[i]
	p += 1
v = max(k[0], k[1], k[2])
if k[0] == v:
	print('chest')
if k[1] == v:
	print('biceps')
if k[2] == v:
	print('back')


n = int(input())
l = list(map(int, input().split()))
(c1, c2, i) = (0, 0, 0)
while i < n:
	if i % 3 == 0:
		c1 += l[i]
	if i % 3 == 1:
		c2 += l[i]
	i += 1
if max(c1, c2, sum(l) - c1 - c2) == c1:
	print('chest')
elif max(c1, c2, sum(l) - c1 - c2) == c2:
	print('biceps')
else:
	print('back')


f = lambda : map(int, input().split())
a = int(input())
e = list(f())
l = [0] * 3
for i in range(a):
	l[i % 3] += e[i]
print('chest' if max(l) == l[0] else ['biceps', 'back'][max(l) == l[2]])


n = int(input())
a = list(map(int, input().split()))
count = 1
c = []
f = []
h = []
for i in range(len(a)):
	if i % 3 == 0:
		c.append(a[i])
	elif i % 3 == 1:
		f.append(a[i])
	elif i % 3 == 2:
		h.append(a[i])
if sum(h) < sum(c) > sum(f):
	print('chest')
elif sum(h) < sum(f) > sum(c):
	print('biceps')
else:
	print('back')


N = input()
T = [int(x) for x in input().split()]
exer = {0: 0, 1: 0, 2: 0}
res = {0: 'chest', 1: 'biceps', 2: 'back'}
for i in range(len(T)):
	exer[i % 3] += T[i]
print(res[max(exer, key=exer.get)])


import sys
from math import sqrt, floor, factorial
from collections import deque
inp = sys.stdin.readline
read = lambda : list(map(int, inp().strip().split()))

def solve():
	n = int(inp())
	arr = [0, 0, 0]
	arr1 = read()
	arr2 = ['chest', 'biceps', 'back']
	for (i, elem) in enumerate(arr1):
		arr[i % 3] += elem
	print(arr2[arr.index(max(arr))])
solve()


n = input()
c = [0, 0, 0]
ans = ['chest', 'biceps', 'back']
l = list(map(int, input().split()))
for i in range(int(n)):
	c[i % 3] += l[i]
print(ans[c.index(max(c))])


n = int(input())
L = list(map(int, input().split()))
c = 0
B = 0
b = 0
for i in range(n):
	if i % 3 == 0:
		c += L[i]
	elif (i - 1) % 3 == 0:
		B += L[i]
	else:
		b += L[i]
D = {c: 'chest', B: 'biceps', b: 'back'}
print(D[max(c, B, b)])


l1 = 0
l2 = 0
l3 = 0
n = int(input())
x = [int(q) for q in input().split()]
for i in range(len(x)):
	if i % 3 == 0:
		l1 += x[i]
	if i % 3 == 1:
		l2 += x[i]
	if i % 3 == 2:
		l3 += x[i]
q = max(l1, l2, l3)
if q == l1:
	print('chest')
if q == l2:
	print('biceps')
if q == l3:
	print('back')


n = int(input())
x = list(map(int, input().split()))
i = 0
(a, b, c) = (0, 0, 0)
while i < n:
	if i % 3 == 0:
		a += x[i]
	elif i % 3 == 1:
		b += x[i]
	else:
		c += x[i]
	i += 1
if a == max(a, b, c):
	print('chest')
elif b == max(a, b, c):
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
s = []
s.append(sum(a[0::3]))
s.append(sum(a[1::3]))
s.append(sum(a[2::3]))
if s.index(max(s)) == 0:
	print('chest')
if s.index(max(s)) == 1:
	print('biceps')
if s.index(max(s)) == 2:
	print('back')


n = int(input())
l = list(map(int, input().split()))
(c, bc, bk) = (0, 0, 0)
for i in range(0, n, 3):
	c += l[i]
	if i + 1 < n:
		bc += l[i + 1]
	if i + 2 < n:
		bk += l[i + 2]
ans = max(c, bc, bk)
if c == ans:
	print('chest')
elif bc == ans:
	print('biceps')
else:
	print('back')


import math

def ost(a, b):
	if a % b != 0:
		return 1
	return 0
n = int(input())
data = list(map(int, input().split()))
ans = [0, 0, 0]
for i in range(n):
	ans[i % 3] += data[i]
anss = [ans[i] for i in range(3)]
anss.sort()
if ans[0] == anss[-1]:
	print('chest')
if ans[1] == anss[-1]:
	print('biceps')
if ans[2] == anss[-1]:
	print('back')


n = int(input().strip())
ll = list(map(int, input().split()))
biceps = 0
chest = 0
back = 0
for i in range(n):
	if (i + 1) % 3 == 0:
		back += ll[i]
	elif (i + 1) % 3 == 1:
		chest += ll[i]
	else:
		biceps += ll[i]
if max(biceps, chest, back) == back:
	print('back')
elif max(biceps, chest, back) == chest:
	print('chest')
else:
	print('biceps')


n = int(input())
a = list(map(int, input().split()))
a1 = sum([a[i] for i in range(n) if i % 3 == 0])
a2 = sum([a[i] for i in range(n) if i % 3 == 1])
a3 = sum([a[i] for i in range(n) if i % 3 == 2])
print('chest' if max(a1, a2, a3) == a1 else ['biceps', 'back'][a3 > a2])


def main():
	n = int(input())
	a = list(map(int, input().split(' ')))
	r = [0, 0, 0]
	s = ['chest', 'biceps', 'back']
	ma = 0
	for (i, ai) in enumerate(a):
		r[i % 3] += ai
		if r[i % 3] > r[ma]:
			ma = i % 3
	return s[ma]
print(main())


n = int(input())
l = list(map(int, input().split()))
bir = 0
iki = 0
uc = 0
for i in range(0, len(l), 3):
	try:
		bir += l[i]
		iki += l[i + 1]
		uc += l[i + 2]
	except:
		break
cv = max(bir, iki, uc)
if cv == bir:
	aa = 'chest'
elif cv == iki:
	aa = 'biceps'
elif cv == uc:
	aa = 'back'
print(aa)


n = int(input())
l = [int(x) for x in input().split(' ')]
chest = 0
biceps = 0
back = 0
for i in range(0, n, 3):
	try:
		chest += l[i]
		biceps += l[i + 1]
		back += l[i + 2]
	except IndexError:
		if n == 2:
			chest += l[i]
			biceps += l[i + 1]
		elif n == 1:
			chest += l[i]
maxexe = max(chest, biceps, back)
if maxexe == chest:
	print('chest')
elif maxexe == biceps:
	print('biceps')
else:
	print('back')


N = int(input())
l = list(map(int, input().split()))
chest = 0
biceps = 0
back = 0
for i in range(0, len(l)):
	if i % 3 == 0:
		chest += l[i]
	elif i % 3 == 1:
		biceps += l[i]
	elif i % 3 == 2:
		back += l[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
su = 0
c = 0
if n > 3:
	for i in range(n // 3 + n % 3 + (n % 3 == 0)):
		if su < sum(l[i::3]):
			su = sum(l[i::3])
			c = i
	print(['chest', 'biceps', 'back'][c])
else:
	print(['chest', 'biceps', 'back'][l.index(max(l))])


n = int(input())
a = list(map(int, input().split()))
a.insert(0, '')
chest = 0
biceps = 0
back = 0
for i in range(1, n + 1):
	if i % 3 == 1:
		chest += a[i]
	elif i % 3 == 2:
		biceps += a[i]
	else:
		back += a[i]
dic = {biceps: 'biceps', chest: 'chest', back: 'back'}
yo = max(list(dic.keys()))
print(dic[yo])


def solve(n, a):
	chest = sum(a[0::3])
	biceps = sum(a[1::3])
	back = sum(a[2::3])
	if chest > biceps and chest > back:
		return 'chest'
	if biceps > chest and biceps > back:
		return 'biceps'
	if back > chest and back > biceps:
		return 'back'

def main():
	n = int(input())
	a = list(map(int, input().split()))
	print(solve(n, a))
main()


PARTS = ['chest', 'biceps', 'back']
n = int(input())
xs = list(map(int, input().split()))
body = [[0, PARTS[i]] for i in range(len(PARTS))]
phase = 0
for x in xs:
	body[phase][0] += x
	phase = (phase + 1) % len(PARTS)
maxi = sorted(body, reverse=True)[0]
print(maxi[1])


def training(repetitions):
	chest = 0
	biceps = 0
	back = 0
	for value in range(0, len(repetitions), 3):
		chest += repetitions[value]
	for value in range(1, len(repetitions), 3):
		biceps += repetitions[value]
	for value in range(2, len(repetitions), 3):
		back += repetitions[value]
	training_list = [chest, biceps, back]
	if max(training_list) == chest:
		return 'chest'
	elif max(training_list) == biceps:
		return 'biceps'
	else:
		return 'back'
number_of_repetitions = int(input())
workouts = list(map(int, input().split()))
print(training(workouts))


(n, chest, biceps, back, count) = (int(input()), 0, 0, 0, 0)
l = [int(ele) for ele in input().split()]
for e in l:
	if count % 3 == 0:
		(chest, count) = (chest + e, count + 1)
	elif (count - 1) % 3 == 0:
		(biceps, count) = (biceps + e, count + 1)
	elif (count - 2) % 3 == 0:
		(back, count) = (back + e, count + 1)
if chest == max(chest, biceps, back):
	print('chest')
elif biceps == max(chest, biceps, back):
	print('biceps')
elif back == max(chest, biceps, back):
	print('back')


s = input()
a = list(map(int, input().split()))
s1 = sum(a[::3])
s2 = sum(a[1::3])
s3 = sum(a[2::3])
if s3 > s1 and s3 > s2:
	print('back')
elif s2 > s1 and s2 > s3:
	print('biceps')
elif s1 > s3 and s1 > s2:
	print('chest')


n = int(input())
exercises = [int(x) for x in input().split()]

def exercise(arr):
	chest = 0
	biceps = 0
	back = 0
	for i in range(len(arr)):
		if i % 3 == 1:
			biceps += arr[i]
		elif i % 3 == 2:
			back += arr[i]
		else:
			chest += arr[i]
	if chest == max(chest, biceps, back):
		return 'chest'
	if biceps == max(chest, biceps, back):
		return 'biceps'
	return 'back'
print(exercise(exercises))


n = int(input())
arr = list(map(int, input().split()))
m = {1: 0, 2: 0, 3: 0}
for i in range(n):
	m[i % 3 + 1] += arr[i]
k = [1, 2, 3]
v = list(m.values())
if k[v.index(max(v))] == 1:
	print('chest')
elif k[v.index(max(v))] == 2:
	print('biceps')
else:
	print('back')


n = int(input())
a = map(int, input().split())
x = list(a)
b = 0
chest = x[::3]
biceps = x[1::3]
back = x[2::3]
ch = sum(chest)
bi = sum(biceps)
ba = sum(back)
if ch >= bi:
	if ch >= ba:
		print('chest')
	else:
		print('back')
elif bi >= ch:
	if bi >= ba:
		print('biceps')
	else:
		print('back')


n = int(input())
l = list(map(int, input().split()))
bi = ba = ch = 0
for i in range(0, n, 3):
	ch += l[i]
for i in range(1, n, 3):
	bi += l[i]
for i in range(2, n, 3):
	ba += l[i]
ma = max(bi, ba, ch)
if ma == bi:
	print('biceps')
elif ma == ba:
	print('back')
else:
	print('chest')


n = int(input())
a = list(map(int, input().split()))
LIST = [0, 0, 0]
idx = 0
for i in range(0, n):
	LIST[i % 3] += a[i]
	if LIST[idx] < LIST[i % 3]:
		idx = i % 3
if idx == 0:
	print('chest')
elif idx == 1:
	print('biceps')
else:
	print('back')


import bisect
import decimal
from decimal import Decimal
import os
from collections import Counter
import bisect
from collections import defaultdict
import math
import random
import heapq
from math import sqrt
import sys
from functools import reduce, cmp_to_key
from collections import deque
import threading
from itertools import combinations
from io import BytesIO, IOBase
from itertools import accumulate
decimal.getcontext().prec = 46

def primeFactors(n):
	prime = set()
	while n % 2 == 0:
		prime.add(2)
		n = n // 2
	for i in range(3, int(math.sqrt(n)) + 1, 2):
		while n % i == 0:
			prime.add(i)
			n = n // i
	if n > 2:
		prime.add(n)
	return list(prime)

def getFactors(n):
	factors = []
	i = 1
	while i <= math.sqrt(n):
		if n % i == 0:
			if n // i == i:
				factors.append(i)
			else:
				factors.append(i)
				factors.append(n // i)
		i = i + 1
	return factors

def SieveOfEratosthenes(n):
	prime = [True for i in range(n + 1)]
	p = 2
	while p * p <= n:
		if prime[p] == True:
			for i in range(p * p, n + 1, p):
				prime[i] = False
		p += 1
	num = []
	for p in range(2, n + 1):
		if prime[p]:
			num.append(p)
	return num

def lcm(a, b):
	return a * b // math.gcd(a, b)

def sort_dict(key_value):
	return sorted(key_value.items(), key=lambda kv: (kv[1], kv[0]))

def list_input():
	return list(map(int, input().split()))

def num_input():
	return map(int, input().split())

def string_list():
	return list(input())

def decimalToBinary(n):
	return bin(n).replace('0b', '')

def binaryToDecimal(n):
	return int(n, 2)

def solve():
	n = int(input())
	arr = list_input()
	chest = back = bicep = 0
	for i in range(3):
		for j in range(i, n, 3):
			if i == 0:
				chest += arr[j]
			elif i == 1:
				bicep += arr[j]
			else:
				back += arr[j]
	maxx = max(chest, bicep, back)
	if maxx == chest:
		print('chest')
	elif maxx == bicep:
		print('biceps')
	else:
		print('back')
t = 1
for _ in range(t):
	solve()


import math
t = int(input())
x = list(map(int, input().split()))
v1 = 0
v2 = 0
v3 = 0
for i in range(math.floor(t / 3)):
	v1 += x[3 * i]
	v2 += x[3 * i + 1]
	v3 += x[3 * i + 2]
ins = t % 3
if ins == 1:
	v1 += x[-1]
elif ins == 2:
	v2 += x[-1]
	v1 += x[-2]
ans = [v1, v2, v3]
if ans.index(max(ans)) == 0:
	print('chest')
elif ans.index(max(ans)) == 1:
	print('biceps')
else:
	print('back')


holds = int(input())
arr = list(map(int, input().strip().split()))
(chest, biceps, back) = (0, 0, 0)
x = 1
for i in arr:
	if x == 1:
		chest += i
		x += 1
	elif x == 2:
		biceps += i
		x += 1
	else:
		back += i
		x = 1
if chest == max([chest, biceps, back]):
	print('chest')
elif biceps == max([chest, biceps, back]):
	print('biceps')
else:
	print('back')


n = int(input())
exercises = list(map(int, input().split()))
history = {'chest': 0, 'biceps': 0, 'back': 0}
for i in range(n):
	if i % 3 == 0:
		history['chest'] += exercises[i]
	if i % 3 == 1:
		history['biceps'] += exercises[i]
	if i % 3 == 2:
		history['back'] += exercises[i]
max_name = 'chest'
for key in history.keys():
	if history[key] > history[max_name]:
		max_name = key
print(max_name)


def answer():
	a = int(input())
	c = [int(x) for x in input().split()]
	i = 0
	d = [0, 0, 0]
	e = ['chest', 'biceps', 'back']
	while i < len(c):
		d[i % 3] += c[i]
		i += 1
	print(e[d.index(max(d))])
answer()


n = int(input())
arr = list(map(int, input().split()))
chest = 0
bis = 0
back = 0
for i in range(0, n, 3):
	chest += arr[i]
for i in range(1, n, 3):
	bis += arr[i]
for i in range(2, n, 3):
	back += arr[i]
if max(chest, bis, back) == chest:
	print('chest')
elif max(chest, bis, back) == bis:
	print('biceps')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
res = [0] * 3
for i in range(n):
	res[i % 3] += l[i]
re = res.index(max(res))
if re == 0:
	print('chest')
elif re == 1:
	print('biceps')
else:
	print('back')


n = int(input())
a = [int(x) for x in input().split()]
chest = 0
biceps = 0
back = 0
for i in range(0, n):
	if (i + 1) % 3 == 1:
		chest = chest + a[i]
	elif (i + 1) % 3 == 2:
		biceps = biceps + a[i]
	elif (i + 1) % 3 == 0:
		back = back + a[i]
if max(chest, biceps, back) == chest:
	print('chest')
elif max(chest, biceps, back) == biceps:
	print('biceps')
elif max(chest, biceps, back) == back:
	print('back')


x = int(input())
y = list(map(int, input().split()))
d = {'chest': 0, 'biceps': 0, 'back': 0}
for (i, j) in enumerate(y):
	if i % 3 == 0:
		d['chest'] += j
	elif i % 3 == 1:
		d['biceps'] += j
	else:
		d['back'] += j
c = list(d.values())
d = list((k for (k, j) in d.items() if j == max(c)))
print(*d, sep='')


n = int(input())
a = list(map(int, input().split()))
chest = 0
bicep = 0
back = 0
i = 0
j = 1
k = 2
length = len(a)
cond = 0
while True:
	if length < 3:
		if length > 1:
			chest = a[0]
			bicep = a[1]
			break
		else:
			chest = a[0]
			break
	else:
		chest = chest + a[i]
		bicep = bicep + a[j]
		back = back + a[k]
		i += 3
		j += 3
		k += 3
		if i >= length:
			break
		if i >= length:
			i = 0
			a[0] = 0
		if j >= length:
			j = 1
			a[j] = 0
		if k >= length:
			k = 2
			a[k] = 0
if chest > bicep and chest > back:
	print('chest')
elif bicep > chest and bicep > back:
	print('biceps')
elif back > chest and back > bicep:
	print('back')


n = int(input())
arr = [int(x) for x in input().split()]
ans = {0: ['chest', 0], 1: ['biceps', 0], 2: ['back', 0]}
for i in range(len(arr)):
	ans[i % 3][1] += arr[i]
print(ans[max(ans.keys(), key=lambda k: ans[k][1])][0])


n = int(input())
ln = list(map(int, input().split()))
a = []
b = []
c = []
a.append(ln[0:n:3])
b.append(ln[1:n:3])
c.append(ln[2:n:3])
f = sum(a[0])
g = sum(b[0])
h = sum(c[0])
dd = max(f, g, h)
if dd == f:
	print('chest')
elif dd == g:
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
answer = {0: 'chest', 1: 'biceps', 2: 'back'}
repitation = [0, 0, 0]
for i in range(n):
	if (i + 1) % 3 == 0:
		repitation[2] += a[i]
	elif (i + 1) % 3 == 2:
		repitation[1] += a[i]
	else:
		repitation[0] += a[i]
maxValue = 0
index = None
for (i, v) in enumerate(repitation):
	if v > maxValue:
		maxValue = v
		index = i
print(answer[index])


n = int(input())
array1 = list(map(int, input().split(' ')))
a = []
b = []
c = []
for i in range(0, n, 3):
	a.append(array1[i])
for i in range(1, n, 3):
	b.append(array1[i])
for i in range(2, n, 3):
	c.append(array1[i])
d = sum(a)
e = sum(b)
f = sum(c)
maximum = max(d, e, f)
if maximum == d:
	print('chest')
elif maximum == e:
	print('biceps')
else:
	print('back')


a = int(input())
b = input()
c = b.split(' ')
d = 1
s1 = 0
s2 = 0
s3 = 0
for i in c:
	if d % 3 == 1:
		s1 += int(i)
	elif d % 3 == 2:
		s2 += int(i)
	else:
		s3 += int(i)
	d += 1
if max(max(s1, s2), s3) == s1:
	print('chest')
elif max(max(s1, s2), s3) == s2:
	print('biceps')
else:
	print('back')


ex = ['chest', 'biceps', 'back']
n = int(input())
rep = [int(c) for c in input().split()]
counter = [0] * 3
for i in range(n):
	counter[i % 3] += rep[i]
(idx, _max) = (-1, 0)
for i in range(3):
	if counter[i] > _max:
		_max = counter[i]
		idx = i
print(ex[idx])


import sys
inp = sys.stdin.readline
out = sys.stdout.write

def ii():
	return int(inp())

def mi():
	return map(int, inp().strip().split())

def li():
	return list(map(int, inp().strip().split()))
n = ii()
l = li()
c1 = 0
c2 = 0
c3 = 0
for i in range(n):
	if (i + 1) % 3 == 1:
		c1 += l[i]
	elif (i + 1) % 3 == 2:
		c2 += l[i]
	else:
		c3 += l[i]
m = max(c1, c2, c3)
if c1 == m:
	print('chest')
elif c2 == m:
	print('biceps')
else:
	print('back')


def main():
	n = int(input())
	exercises = [int(_) for _ in input().split()]
	chest = sum(exercises[0:n:3])
	biceps = sum(exercises[1:n:3])
	back = sum(exercises[2:n:3])
	max_exercises = max(chest, biceps, back)
	print('chest' if chest == max_exercises else 'biceps' if biceps == max_exercises else 'back')
main()


n = int(input())
repeats = [int(i) for i in input().split()]
exercises = ['chest', 'biceps', 'back']
total = [0, 0, 0]
for i in range(n):
	if i in range(0, n, 3):
		total[0] += repeats[i]
	if i in range(1, n, 3):
		total[1] += repeats[i]
	if i in range(2, n, 3):
		total[2] += repeats[i]
solution = exercises[total.index(max(total))]
print(solution)


a = int(input())
l = list(map(int, input().split()))
biceps = 0
back = 0
chest = 0
t = []
for i in range(0, a, 3):
	chest += l[i]
for i in range(1, a, 3):
	biceps += l[i]
for i in range(2, a, 3):
	back += l[i]
t.append(chest)
t.append(biceps)
t.append(back)
k = t.index(max(t))
if k == 0:
	print('chest')
elif k == 1:
	print('biceps')
else:
	print('back')


a = int(input())
b = list(map(int, input().split()))
c = len(b)
o = 3
f = 0
x = 0
y = 0
z = 0
for i in b:
	k = b[f:o]
	if len(k) == 3:
		x = x + k[0]
		y = y + k[1]
		z = z + k[2]
	elif len(k) == 2:
		x = x + k[0]
		y = y + k[1]
	elif len(k) == 1:
		x = x + k[0]
	o = o + 3
	f = f + 3
if x > y and x > z:
	print('chest')
elif y > x and y > z:
	print('biceps')
elif z > x and z > y:
	print('back')


n = int(input())
l = list(map(int, input().split()))
d = {sum(l[0::3]): 'chest', sum(l[1::3]): 'biceps', sum(l[2::3]): 'back'}
print(d[max(sum(l[0::3]), sum(l[1::3]), sum(l[2::3]))])


import math
import sys
n = int(input())
b = [0, 0, 0]
c = ['chest', 'biceps', 'back']
arr = list(map(int, input().split()))
for j in range(0, n):
	b[j % 3] += arr[j]
print(c[b.index(max(b))])


n = int(input())
exercicios = input().split(' ')
biceps = 0
back = 0
chest = 0
for x in range(0, n, 3):
	chest += int(exercicios[x])
for x in range(1, n, 3):
	biceps += int(exercicios[x])
for x in range(2, n, 3):
	back += int(exercicios[x])
lista = [chest, back, biceps]
y = sorted(lista)
if y[2] == chest:
	print('chest')
elif y[2] == biceps:
	print('biceps')
else:
	print('back')


n = int(input(''))
t = list(map(int, input('').split()))
p = 0
q = 0
r = 0
for i in range(0, len(t), 3):
	p = p + t[i]
	j = i + 1
	k = i + 2
	if j < len(t):
		q = q + t[j]
	if k < len(t):
		r = r + t[k]
s = [p, q, r]
if max(s) == p:
	print('chest')
if max(s) == q:
	print('biceps')
if max(s) == r:
	print('back')


def workout(arr):
	chest = 0
	biceps = 0
	back = 0
	flag = 1
	for i in arr:
		if flag == 1:
			chest += i
			flag += 1
		elif flag == 2:
			biceps += i
			flag += 1
		elif flag == 3:
			back += i
			flag = 1
	big = max(chest, biceps, back)
	if chest == big:
		return 'chest'
	elif biceps == big:
		return 'biceps'
	return 'back'
n = int(input())
ar = list(map(int, input().rstrip().split()))
print(workout(ar))


n = int(input())
L = list(map(int, input().split()))
A = [0, 0, 0]
for i in range(n):
	A[i % 3] += L[i]
if max(A) == A[0]:
	print('chest')
elif max(A) == A[1]:
	print('biceps')
else:
	print('back')


(n, a) = (int(input()), list(map(int, input().split())))
(x, y, z) = [sum(a[_::3]) for _ in range(3)]
t = max(x, max(y, z))
print('chest' if x == t else 'biceps' if y == t else 'back')


n = int(input())
a = list(map(int, input().split()))
count = [sum(a[::3]), sum(a[1::3]), sum(a[2::3])]
output = ['chest', 'biceps', 'back']
print(output[count.index(max(count))])


n = int(input())
a = list(map(int, input().split()))
from collections import defaultdict
d = defaultdict(list)
for i in range(0, len(a)):
	m = i % 3
	d[m].append(a[i])
d = dict(d)
x = max(d.items(), key=lambda x: sum(x[1]))[0]
if x == 0:
	print('chest')
elif x == 1:
	print('biceps')
elif x == 2:
	print('back')


import sys
my_file = sys.stdin
n = int(my_file.readline().strip('\n'))
a = [int(i) for i in my_file.readline().split()]
if sum(a[::3]) >= sum(a[1::3]) and sum(a[::3]) >= sum(a[2::3]):
	print('chest')
elif sum(a[1::3]) >= sum(a[::3]) and sum(a[1::3]) >= sum(a[2::3]):
	print('biceps')
else:
	print('back')


import sys

def check(exs):
	(chest, bi, back) = (0, 0, 0)
	for (i, x) in enumerate(exs):
		module = i % 3
		if module == 0:
			chest += x
		elif module == 1:
			bi += x
		else:
			back += x
	if chest > bi and chest > back:
		print('chest')
	elif bi > chest and bi > back:
		print('biceps')
	else:
		print('back')

def main():
	n = int(sys.stdin.readline())
	arr = map(int, sys.stdin.readline().split())
	check(arr)
main()


x = int(input())
arr = list(map(int, input().split()))
chest = sum(arr[::3])
biceps = sum(arr[1::3])
back = sum(arr[2::3])
arr = [chest, biceps, back]
print(('chest', 'biceps', 'back')[arr.index(max(arr))])


n1 = int(input())
a = [int(x) for x in input().split()]
n = len(a)
bi = 0
ch = 0
ba = 0
for i in range(0, n, 3):
	ch = ch + a[i]
for i in range(1, n, 3):
	bi += a[i]
for i in range(2, n, 3):
	ba += a[i]
if ch > bi and ch > ba:
	print('chest')
elif bi > ch and bi > ba:
	print('biceps')
else:
	print('back')


n = int(input())
t = list(map(int, input().split()))
e = [0, 0, 0]
for i in range(n):
	e[i % 3] += t[i]
f = max(enumerate(e), key=lambda x: x[1])
if f[0] == 0:
	print('chest')
elif f[0] == 1:
	print('biceps')
else:
	print('back')


x = int(input())
y = [int(i) for i in input().split()]
a = y[::3]
b = y[1::3]
c = y[2::3]
aa = 0
bb = 0
cc = 0
aa = sum([int(i) for i in a])
bb = sum([int(i) for i in b])
cc = sum([int(i) for i in c])
if max(aa, bb, cc) == aa:
	print('chest')
elif max(aa, bb, cc) == bb:
	print('biceps')
else:
	print('back')


import sys
n = int(sys.stdin.readline())
l = [int(x) for x in sys.stdin.readline().split()]
chest = 0
biceps = 0
back = 0
i = 0
while i < n:
	chest += l[i]
	i += 3
i = 1
while i < n:
	biceps += l[i]
	i += 3
i = 2
while i < n:
	back += l[i]
	i += 3
if chest >= biceps and chest >= back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
elif back > biceps and back > chest:
	print('back')


import sys

def data():
	return sys.stdin.readline().strip()

def sp():
	return map(int, data().split())

def l():
	return list(sp())
n = int(data())
reps = l()
ex = ['chest', 'biceps', 'back']
chest = 0
biceps = 0
back = 0
for i in range(n):
	if i % 3 == 0:
		chest = chest + reps[i]
		i += 3
	if i % 3 == 1:
		biceps += reps[i]
		i += 3
	if i % 3 == 2:
		back += reps[i]
		i += 3
if max(chest, biceps, back) == chest:
	print('chest')
if max(chest, biceps, back) == biceps:
	print('biceps')
if max(chest, biceps, back) == back:
	print('back')


L = [0, 0, 0]
L1 = ['chest', 'biceps', 'back']
input()
for (k, j) in enumerate(map(int, input().split(' '))):
	L[k % 3] += j
print(L1[L.index(max(L))])


n = int(input())
data = list(map(int, input().split()))
chest = sum((data[i] for i in range(0, len(data), 3)))
biceps = sum((data[i] for i in range(1, len(data), 3)))
back = sum((data[i] for i in range(2, len(data), 3)))
if max(chest, biceps, back) == chest:
	print('chest')
elif max(chest, biceps, back) == biceps:
	print('biceps')
else:
	print('back')


n = int(input())
a = input().split()
for i in range(n):
	a[i] = int(a[i])
g = 0
b = 0
s = 0
for i in range(0, n, 3):
	g = g + a[i]
	if i + 1 < n:
		b = b + a[i + 1]
	if i + 2 < n:
		s = s + a[i + 2]
if g == max(g, b, s):
	print('chest')
elif b == max(g, b, s):
	print('biceps')
else:
	print('back')


n = int(input())
A = input().split()
chest = 0
biceps = 0
back = 0
k = 0
for i in A:
	i = int(i)
	if k == 0:
		chest += i
	elif k == 1:
		biceps += i
	else:
		back += i
	k += 1
	k = k % 3
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


import math
n = int(input())
a = [int(x) for x in input().split()]
cnt = [0] * 3
for i in range(n):
	cnt[i % 3] += a[i]
ma = 0
for i in range(3):
	ma = max(ma, cnt[i])
s = ['chest', 'biceps', 'back']
for i in range(3):
	if cnt[i] == ma:
		print(s[i])
		exit(0)


n = int(input())
a = list(map(int, input().split()))
b = ['chest', 'biceps', 'back']
if len(a) <= 3:
	print(b[a.index(max(a))])
else:
	i = 0
	j = 0
	k = 0
	for _ in range(len(a)):
		if _ % 3 == 0:
			i += a[_]
		elif _ % 3 == 1:
			j += a[_]
		else:
			k += a[_]
	if i == max(i, j, k):
		print('chest')
	elif j == max(i, j, k):
		print('biceps')
	else:
		print('back')


n = int(input())
arr = list(map(int, input().split()))
(ch, bi, ba) = (0, 0, 0)
for i in range(n):
	if i % 3 == 0:
		ch += arr[i]
	elif i % 3 == 1:
		bi += arr[i]
	else:
		ba += arr[i]
if ch > bi and ch > ba:
	print('chest')
elif bi > ch and bi > ba:
	print('biceps')
else:
	print('back')


input()
arr = input().split(' ')
data = []
data.append(0)
data.append(0)
data.append(0)
k = 0
for i in range(0, len(arr)):
	data[k] = data[k] + int(arr[i])
	k = k + 1
	if k > 2:
		k = 0
index = data.index(max(data))
if index == 0:
	print('chest')
if index == 1:
	print('biceps')
if index == 2:
	print('back')


n = int(input())
x = list(map(int, input().split()))
l = []
t = []
v = []
a = 0
b = 0
c = 0
for i in range(1, n + 1):
	if i % 3 == 1:
		l.append(x[i - 1])
	elif i % 3 == 2:
		t.append(x[i - 1])
	else:
		v.append(x[i - 1])
a = sum(l)
b = sum(t)
c = sum(v)
if a > b and a > c:
	print('chest')
elif b > a and b > c:
	print('biceps')
else:
	print('back')


import sys
import math as m

def main():
	pass

def binary(n):
	return bin(n).replace('0b', '')

def decimal(s):
	return int(s, 2)

def pow2(n):
	p = 0
	while n > 1:
		n //= 2
		p += 1
	return p

def isPrime(n):
	if n == 1:
		return False
	else:
		root = int(n ** 0.5)
		root += 1
		for i in range(2, root):
			if n % i == 0:
				return False
		return True

def lts(l):
	s = ''.join(map(str, l))
	return s

def stl(s):
	l = list(s)
	return l
mod = int(1000000000.0) + 7

def sinp():
	return sys.stdin.readline().strip()

def iinp():
	return int(input())

def ninp():
	return map(int, sys.stdin.readline().strip().split())

def linp():
	return list(map(int, sys.stdin.readline().strip().split()))

def p(a):
	print(a)

def p2(a, b):
	print(a, b)
n = iinp()
a = linp()
chest = a[0::3]
c1 = sum(chest)
biceps = a[1::3]
b1 = sum(biceps)
back = a[2::3]
bs = sum(back)
if max(c1, b1, bs) == c1:
	print('chest')
elif max(c1, b1, bs) == b1:
	print('biceps')
elif max(c1, b1, bs) == bs:
	print('back')


n = int(input())
repeats = list(map(int, input().split()))
muscle_count = [0, 0, 0]
i = 0
for repeat in repeats:
	muscle_count[i] += repeat
	i = (i + 1) % 3
muscle = ['chest', 'biceps', 'back'][muscle_count.index(max(muscle_count))]
print(muscle)


n = int(input())
l = list(map(int, input().split()))
i = 0
sc = 0
sb = 0
sa = 0
while i < n:
	sc += l[i]
	i += 3
i = 1
while i < n:
	sb += l[i]
	i += 3
i = 2
while i < n:
	sa += l[i]
	i += 3
if sc > sb and sc > sa:
	print('chest')
elif sb > sc and sb > sa:
	print('biceps')
else:
	print('back')


b = [0, 0, 0]
c = 0
n = int(input())
e = list(map(int, input().split()))
for i in e:
	if c == 3:
		c = 0
	b[c] = i + b[c]
	c += 1
if max(b) == b[0]:
	print('chest')
elif max(b) == b[1]:
	print('biceps ')
else:
	print('back')


n = int(input())
l = list(map(int, input().split()))
p1 = 0
p2 = 0
p3 = 0
t = 1
for i in range(n):
	c = 1
	if t == 1 and c != 0:
		p1 = p1 + l[i]
		t = t + 1
		c = 0
	if t == 2 and c != 0:
		p2 = p2 + l[i]
		t = t + 1
		c = 0
	if t == 3 and c != 0:
		p3 = p3 + l[i]
		t = 1
		c = 0
if p1 > p2 and p1 > p3:
	print('chest')
if p2 > p1 and p2 > p3:
	print('biceps')
if p3 > p1 and p3 > p2:
	print('back')


n = int(input())
l = list(map(int, input().split(' ')))
(gr, bic, spina) = (0, 0, 0)
for i in range(0, len(l)):
	if i % 3 == 0:
		gr += l[i]
	if i % 3 == 1:
		bic += l[i]
	if i % 3 == 2:
		spina += l[i]
if spina == max(gr, bic, spina):
	print('back')
if gr == max(gr, bic, spina):
	print('chest')
if bic == max(gr, bic, spina):
	print('biceps')


import sys
from math import *
input = sys.stdin.readline
RI = lambda : [int(x) for x in sys.stdin.readline().strip().split()]
rw = lambda : input().strip().split()
ls = lambda : list(input().strip())
from collections import defaultdict as df
import heapq
infinite = float('inf')
n = int(input())
l = RI()
i = 0
chest = 0
biceps = 0
back = 0
while i < n - 2:
	chest += l[i]
	biceps += l[i + 1]
	back += l[i + 2]
	i += 3
if i == n - 2:
	chest += l[i]
	biceps += l[i + 1]
if i == n - 1:
	chest += l[i]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


a = int(input())
x = list(map(int, input().split()))
n1 = a % 3
n = int(a / 3)
if n1 != 0:
	n = n + 1
s1 = 0
s2 = 0
s3 = 0
for i in range(0, n * 3, 3):
	s1 = s1 + x[i]
if n1 == 2 or n1 == 0:
	r = n
else:
	r = n - 1
for i in range(1, r * 3, 3):
	s2 = s2 + x[i]
for i in range(2, len(x), 3):
	s3 = s3 + x[i]
m1 = max(s1, s2, s3)
if m1 == s1:
	print('chest')
elif m1 == s2:
	print('biceps')
elif m1 == s3:
	print('back')


from sys import stdin, stdout
input = stdin.readline
n = int(input())
a = list(map(int, input().split()))
ch = bi = ba = 0
for i in range(n):
	if i % 3 == 0:
		ch += a[i]
	elif i % 3 == 1:
		bi += a[i]
	else:
		ba += a[i]
if ch > bi and ch > ba:
	stdout.write('chest')
elif bi > ch and bi > ba:
	stdout.write('biceps')
else:
	stdout.write('back')


n = int(input())
a = input().split(' ')
(ch, bi, ba) = (0, 0, 0)
for i in range(n):
	a[i] = int(a[i])
if n >= 3:
	for j in range(0, n, 3):
		ch += a[j]
	for k in range(1, n, 3):
		bi += a[k]
	for l in range(2, n, 3):
		ba += a[l]
	x = max(ch, bi, ba)
	if ch == x:
		print('chest')
	elif bi == x:
		print('biceps')
	else:
		print('back')
elif n == 2:
	if a[0] >= a[1]:
		print('chest')
	else:
		print('biceps')
else:
	print('chest')


n = int(input())
l = list(map(int, input().split()))
(x, y, z) = (0, 0, 0)
for i in range(n):
	f = i % 3
	if f == 0:
		x = x + l[i]
	elif f == 1:
		y = y + l[i]
	else:
		z = z + l[i]
m = max(x, y, z)
if m == x:
	print('chest')
elif m == y:
	print('biceps')
else:
	print('back')


n = int(input())
exercises = tuple(map(int, input().split()))
i = 0
(chest, biceps, back) = (0, 0, 0)
while True:
	if i < n:
		chest += exercises[i]
	else:
		break
	if i + 1 < n:
		biceps += exercises[i + 1]
	else:
		break
	if i + 2 < n:
		back += exercises[i + 2]
	else:
		break
	i += 3
max_value = max(chest, biceps, back)
if max_value == chest:
	print('chest')
elif max_value == biceps:
	print('biceps')
else:
	print('back')


exercises = int(input())
repeats = list(map(int, input().split()))
length = len(repeats)
chest = 0
biceps = 0
back = 0
for exercise in range(length):
	if exercise % 3 == 0:
		chest += repeats[exercise]
	elif exercise % 3 == 1:
		biceps += repeats[exercise]
	elif exercise % 3 == 2:
		back += repeats[exercise]
if chest > biceps and chest > back:
	print('chest')
elif biceps > chest and biceps > back:
	print('biceps')
else:
	print('back')


n = int(input())
a = input().split(' ')
sum1 = []
for i in range(n):
	a[i] = int(a[i])
for i in range(3):
	j = i
	sum = 0
	while j <= n - 1:
		sum += a[j]
		j += 3
	sum1.append(sum)
max = 0
j = 0
for i in range(len(sum1)):
	if sum1[i] > max:
		max = sum1[i]
		j = i
if j == 0:
	print('chest')
if j == 1:
	print('biceps')
if j == 2:
	print('back')


n = int(input())
l = list(map(int, input().split()))
c = 0
b = 0
ba = 0
i = 0
while i != n:
	c = c + l[i]
	i = i + 1
	if i != n:
		b = b + l[i]
		i = i + 1
	if i != n:
		ba = ba + l[i]
		i = i + 1
if c == max(c, b, ba):
	print('chest')
elif b == max(c, b, ba):
	print('biceps')
else:
	print('back')


n = int(input())
a = list(map(int, input().split()))
c = [a[i] for i in range(0, n, 3)]
b = [a[i] for i in range(1, n, 3)]
k = [a[i] for i in range(2, n, 3)]
sc = sum(c)
sb = sum(b)
sk = sum(k)
if sc > sb and sc > sk:
	print('chest')
elif sb > sk and sb > sc:
	print('biceps')
else:
	print('back')


import sys
n = int(input())
an = list(map(int, sys.stdin.readline().split()))
counts = [0, 0, 0]
for i in range(n):
	counts[i % 3] += an[i]
imax = 0
nmax = counts[0]
for i in range(1, 3):
	if counts[i] > nmax:
		imax = i
		nmax = counts[i]
types = ['chest', 'biceps', 'back']
print(types[imax])