Problem:
 Score : 400 points    Problem Statement There are N dishes of cuisine placed in front of Takahashi and Aoki.
For convenience, we call these dishes Dish 1 , Dish 2 , ..., Dish N .  When Takahashi eats Dish i , he earns A_i points of happiness ; when Aoki eats Dish i , she earns B_i points of happiness.  Starting from Takahashi, they alternately choose one dish and eat it, until there is no more dish to eat.
Here, both of them choose dishes so that the following value is maximized: "the sum of the happiness he/she will earn in the end" minus "the sum of the happiness the other person will earn in the end".  Find the value: "the sum of the happiness Takahashi earns in the end" minus "the sum of the happiness Aoki earns in the end".      Constraints  1 \leq N \leq 10^5  1 \leq A_i \leq 10^9  1 \leq B_i \leq 10^9  All values in input are integers.         Input Input is given from Standard Input in the following format:  N  A_1  B_1  :  A_N  B_N       Output Print the value: "the sum of the happiness Takahashi earns in the end" minus "the sum of the happiness Aoki earns in the end".        Sample Input 1 3
10 10
20 20
30 30      Sample Output 1 20  In this sample, both of them earns 10 points of happiness by eating Dish 1 , 20 points by eating Dish 2 , and 30 points by eating Dish 3 .  In this case, since Takahashi and Aoki have the same "taste", each time they will choose the dish with which they can earn the greatest happiness. Thus, first Takahashi will choose Dish 3 , then Aoki will choose Dish 2 , and finally Takahashi will choose Dish 1 , so the answer is (30 + 10) - 20 = 20 .       Sample Input 2 3
20 10
20 20
20 30      Sample Output 2 20  In this sample, Takahashi earns 20 points of happiness by eating any one of the dishes 1, 2 and 3 , but Aoki earns 10 points of happiness by eating Dish 1 , 20 points by eating Dish 2 , and 30 points by eating Dish 3 .  In this case, since only Aoki has likes and dislikes, each time they will choose the dish with which Aoki can earn the greatest happiness. Thus, first Takahashi will choose Dish 3 , then Aoki will choose Dish 2 , and finally Takahashi will choose Dish 1 , so the answer is (20 + 20) - 20 = 20 .       Sample Input 3 6
1 1000000000
1 1000000000
1 1000000000
1 1000000000
1 1000000000
1 1000000000      Sample Output 3 -2999999997  Note that the answer may not fit into a 32 -bit integer.

Solution (Python):
N = int(input())
A = [0] * N
B = [0] * N
Sum = [[0] * 2 for i in range(N)]

for i in range(N):
    A[i], B[i] = map(int, input().split())
    Sum[i][0] = i
    Sum[i][1] = A[i] + B[i]
    
a = 0
b = 0
turn = 0

Sum.sort(key=lambda x:x[1], reverse=True)
    
for i in range(N):
    if turn == 0:
        a += A[Sum[i][0]]
        turn = 1
    else:
        b += B[Sum[i][0]]
        turn = 0

print(a - b)

Solution (Python):

"""
n, a, b = map(int, input().split())
ab = n / 2
ansa = min(a, b)
ansb = max((a+b)-n, 0)
print(ansa,ansb)
"""


"""
n = int(input())
a = input()
b = input()
c = input()
ans = 0
for i in range(n):
    bf = [a[i], b[i], c[i]]
    bf = set(bf)
    ans += len(bf) - 1
print(ans)
"""



n = int(input())
ab = []
aba = []
abb = []
for i in range(n):
    a,b = map(int, input().split())
    ab.append([a + b, i])
    aba.append(a)
    abb.append(b)
ab.sort(reverse = True, key = lambda x:x[0])
ans = 0
for i in range(n):
    if i % 2 == 0:
        ans += aba[ab[i][1]]
    else:
        ans -= abb[ab[i][1]]
print(ans)



"""
n, m = map(int, input().split())
ab = [[] for _ in range(n)]
for i in range(n + m - 1):
    a,b = map(int, input().split())
    ab[a-1].append(b-1)
print(ab)
ans = [0 for i in range(n)]
def yosozero(i):
    if ans[i]
"""

Solution (Python):
from operator import itemgetter
N = int(input())
AB = [list(map(int, input().split())) for _ in range(N)]
A, B = zip(*AB)
ABC = [[A[i], B[i], A[i]+B[i]] for i in range(N)]
ABC.sort(key=itemgetter(2, 0, 1), reverse=True)
ans = 0
for i in range(N):
    if i % 2 == 0:
        ans += ABC[i][0]
    else:
        ans -= ABC[i][1]
print(ans)

Solution (Python):
N = int(input())

A = [[] for i in range(N)]

for i in range(N):
  a, b = [int(j) for j in input().split()]
  c = a + b
  A[i] = [a, b, c]

A.sort(key=lambda x: x[2], reverse=True)

diff = 0

for i in range(N):
  if i % 2 == 0:
    diff += A[i][0]
  else:
    diff -= A[i][1]

print(diff)

Solution (Python):
import sys

n = int(input())
ab = [tuple(map(int, line.split())) for line in sys.stdin.readlines()]
abd = [(a + b, a, b) for a, b in ab]
abd.sort(reverse=True)

print(sum(x[1] for x in abd[::2]) - sum(x[2] for x in abd[1::2]))

Solution (Python):
import sys
fin = sys.stdin.readline


N = int(fin())
happinesses = [tuple(int(elem) for elem in fin().split()) for _ in range(N)]

happinesses.sort(key=lambda x: sum(x), reverse=True)
score = sum(A for A, _ in happinesses[::2]) - sum(B for _, B in happinesses[1::2])
print(score)

Solution (Python):
N = int(input())

dishes = []
for _ in range(N):
  a, b = map(int, input().split())
  dishes.append([a,b,a+b])
  
start = 0
end = N // 2
  
dishesA = sorted(dishes, key = lambda x:x[2])[::-1]

pointA = 0
pointB = 0

      
for i in range(N):
  if i % 2 == 0:
    pointA += dishesA[i][0]
  else:
    pointB += dishesA[i][1]
    
print(pointA - pointB)

Solution (Python):
n=int(input())
A=[]
for i in range(n):
    A.append(list(map(int,input().split())))

A.sort(reverse=1)

B=[]
for i in range(n):
    B.append([i,A[i][1]+A[i][0]])
    
B.sort(reverse=1,key=lambda x:x[1])








S=[0,0]

for i in range(n):
    S[i%2]+=A[B[i][0]][i%2]


print(S[0]-S[1])

Solution (Python):
a = []
b = []
sa = []
wa = []
n = int(input())
for i in range(n):
    p, y = map(int, input().split())
    a.append((p, y))

sa = sorted(a, key=lambda x: x[0] - x[1])
wa = sorted(sa, key=lambda x: x[0]+x[1], reverse=True)
print(sum(x[0] for x in wa[::2])-sum(x[1] for x in wa[1::2]))

Solution (Python):
n = int(input())
A = [[int(i) for i in input().split()] for j in range(n)]

C = []
D = []
i = 0

for a, b in A:
    C.append((a + b, i))
    i += 1

C.sort(reverse=True)
ans = 0

for i, c in enumerate(C):
    if i % 2 == 0:
        ans += A[c[1]][0]
    else:
        ans -= A[c[1]][1]

print(ans)

Solution (Python):
N = int(input())
AB = [list(map(int, input().split())) for i in range(N)]

table = [[0] * 4 for i in range(N)]
for i, (Ai, Bi) in enumerate(AB):
    table[i][0] = Ai
    table[i][1] = Bi 
    table[i][2] = Ai + Bi
    table[i][3] = i

    
table_A = list(table)
table_A.sort(key=lambda x: -x[0])
table_A.sort(key=lambda x: -x[2])

table_B = list(table)
table_B.sort(key=lambda x: -x[1])
table_B.sort(key=lambda x: -x[2])

ans = 0
idx_a = 0
idx_b = 0
state = [0] * N
for i in range(N):
    
    
    if i % 2:
        while True:
            A_tmp, B_tmp, score_tmp, i_tmp = table_B[idx_b]
            if state[i_tmp] < 1:
                
                ans -= B_tmp 
                state[i_tmp] = 1
                idx_b += 1
                break
            idx_b += 1
    else:
        while True:
            A_tmp, B_tmp, score_tmp, i_tmp = table_A[idx_a]
            if state[i_tmp] < 1:
                
                ans += A_tmp
                state[i_tmp] = 1
                idx_a += 1
                break
            idx_a += 1

print(ans)

Solution (Python):


import numpy as np
import scipy

from collections import defaultdict
from pprint import pprint

N = int(input())
A = []
B = []
diff = []
points = [] 
for i in range(N):
    a,b = [int(x) for x in input().split(" ")]
    points.append([a,b,a+b])

sorted_points = sorted(points, key=lambda x: x[2], reverse=True)
point_a, point_b = 0,0

turn_A = True
for p in sorted_points:
    if turn_A:
        point_a += p[0]
        turn_A = False
    else:
        point_b += p[1]
        turn_A = True

print(point_a - point_b)

Solution (Python):
N = int(input())
P = []

for i in range(N):
    A, B = map(int, input().split())
    P.append((A + B, -A, B))

P.sort()
P.reverse()

ans = 0
turn = 1
for i in range(N):
    ans -= P[i][turn]
    turn = 3 - turn

print(ans)

Solution (Python):
N = int(input())
A = [0 for i in range(N)]
B = [0 for i in range(N)]
sums = [0 for i in range(N)]
sum_dic = {}
for i in range(N):
    A[i], B[i] = map(int, input().split())
    sums[i] = A[i] + B[i]
    if sums[i] in sum_dic.keys():
        sum_dic[sums[i]].append(i)
    else:
        sum_dic[sums[i]] = [i]
    
sums.sort(reverse=True)
ans = 0
for i in range(len(sums)):
    if i % 2 == 0:
        ans += A[sum_dic[sums[i]].pop()]
    else:
        ans -= B[sum_dic[sums[i]].pop()]




print(ans)

Solution (Python):
n = int(input())
lis = [list(map(int,input().split())) for i in range(n)]
for i in range(n):lis[i].append(lis[i][1]+lis[i][0])

takahashi = 0
aoki = 0

lis.sort(key = lambda x:x[2],reverse=True)

for i in range(n):
    if i % 2 == 0:
        takahashi += lis[i][0]
    else:
        aoki += lis[i][1]
print(takahashi-aoki)

Solution (Python):
N=int(input())
A=[0 for i in range(N)]
B=[0 for i in range(N)]
for i in range(N):
    A[i],B[i]=map(int,input().split())
X=sorted([(B[i]+A[i],A[i],B[i],i) for i in range(N)])
Y=sorted([(A[i]+B[i],B[i],A[i],i) for i in range(N)])
used=[0 for i in range(N)]
tkhs=0
aoki=0
while(len(X)>0 and len(Y)>0):
    while(True):
        if len(X)>0 and used[X[-1][3]]==1:
            X.pop()
        else:
            break
    if len(X)==0:
        break
    tkhs+=X[-1][1]
    used[X[-1][3]]=1
    X.pop()
    while(True):
        if len(Y)>0 and used[Y[-1][3]]==1:
            Y.pop()
        else:
            break
    if len(Y)==0:
        break
    aoki+=Y[-1][1]
    used[Y[-1][3]]=1
    Y.pop()
print(tkhs-aoki)

Solution (Python):

import numpy as np

N = int(input())
AB = []
for i in range(N):
    AB.append(list(map(int, input().split())))


point = np.zeros(N)
for i in range(N):
    point[i] = AB[i][0] + AB[i][1]

 



pointMaxIndex = np.argsort(-point)


Tpoint = 0
Apoint = 0
for i in range(N):
    if i % 2 == 0:
        Tpoint += AB[pointMaxIndex[i]][0]
    else:
        Apoint += AB[pointMaxIndex[i]][1]

ans = Tpoint - Apoint

print(ans)

Solution (Python):
N = int(input().strip())

sumA = 0
pair_sum = [0] * N
for i in range(N):
  A, B = map(int, input().split())
  pair_sum[i] = A + B
  sumA += A

pair_sum = sorted(pair_sum, reverse=True)
pair_sum_first = 0

for i in range(1, N, 2):
  pair_sum_first += pair_sum[i]
print("%d" % (sumA - pair_sum_first))

Solution (Python):
N = int(input())

An = []
Bn = []

results = dict()
for i in range(N):
    a, b = map(int, input().split())
    hyoka = (a, b)
    wa = a + b
    if wa in results:
        results[wa].append(hyoka)
    else:
        results[wa] = [hyoka]

sa = 0
turn = 1
for _, v in sorted(results.items(), reverse=True):
    for hyoka in v:
        if turn % 2 == 1:
            sa += hyoka[0]
        else:
            sa -= hyoka[1]
        turn += 1
print(sa)

Solution (Python):

N = int(input())
A = [None] * N
B = [None] * N
for i in range(N):
    A[i], B[i] = map(int, input().split())

C = [[A[i] + B[i], i] for i in range(N)]
C.sort(reverse=True)
ans = 0
for i in range(N):
    if i % 2 == 0:
        ans += A[C[i][1]]
    else:
        ans -= B[C[i][1]]
print(ans)

Solution (Python):
N = int(input())

scores = []

for i in range(0, N):
    a, b = [int(i) for i in input().split()]
    scores.append((a + b, a, b))

scores.sort(reverse=True)
result = 0
for i in range(0, N):
    if i % 2 == 0:
        result += scores[i][1]
    else:
        result -= scores[i][2]

print(result)

Solution (Python):
N = int(input())
A = [0] * N
B = [0] * N
ab_sum = [[0] * 2 for _ in range(N)]

for i in range(N):
    a, b = map(int, input().split())
    A[i] = a
    B[i] = b
    ab_sum[i] = [a + b, i]

ab_sum.sort(reverse = True)

a = 0

ans = 0

for i in range(N):
    temp = ab_sum[i][1]
    if i % 2 == 0:
        ans += A[temp]
    else:
        ans -= B[temp]

print(ans)

Solution (Python):
N = int(input())

A_list = []
B_list = []
sum_list = []
ans = 0


for i in range(N):
	A, B = map(int, input().split())
	A_list.append(A)
	B_list.append(B)
	sum_list.append([A+B, i])

sum_list.sort()

for i in range(N):
	point, j = sum_list.pop()
	if i%2 == 0:
		ans += A_list[j]
	else:
		ans -= B_list[j]

print(ans)

Solution (Python):
import numpy as np
N = int(input())
A = np.array([0 for i in range(N)], np.int64)
B = np.array([0 for i in range(N)], np.int64)
TA = 0
AO = 0
for i in range(N):
    A[i], B[i] = map(int, input().split())
AmB = np.array([A[i] + B[i] for i in range(N)])




index = np.argsort(AmB)[::-1]
print(np.sum(A[index[::2]]) - np.sum(B[index[1::2]]))

Solution (Python):
N = int(input())
happiness = []
for i in range(N):
    a, b = map(int, input().split())
    happiness.append((a, b, a+b, i))

T = []
A = []
eaten = [False]*N

happiness1 = sorted(happiness, key=lambda x:(x[2], x[0], x[1]))
happiness2 = sorted(happiness, key=lambda x:(x[2], x[1], x[0]))

for i in range(N):
    if i % 2 == 0: 
        while True:
            a, _, _, idx = happiness1.pop()
            if not eaten[idx]:
                eaten[idx] = True
                T.append(a)
                break
    else: 
        while True:
            _, b, _, idx = happiness2.pop()
            if not eaten[idx]:
                eaten[idx] = True
                A.append(b)
                break

print(sum(T) - sum(A))

Solution (Python):
n = int(input())
AB = []
for i in range(n):
    a, b = map(int, input().split())
    AB.append([a+b, a, b])
AB.sort(reverse=True)

t = 0
for ab in AB[0::2]:
    t += ab[1]

a = 0
for ab in AB[1::2]:
    a += ab[2]
    
print(t - a)

Solution (Python):

import bisect
import heapq
import math
import random
import sys
from collections import Counter, defaultdict, deque
from decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal
from functools import lru_cache, reduce
from itertools import combinations, combinations_with_replacement, product, permutations
from operator import add, mul, sub

sys.setrecursionlimit(10000)


def read_int():
    return int(input())


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


def read_float():
    return float(input())


def read_float_n():
    return list(map(float, input().split()))


def read_str():
    return input().strip()


def read_str_n():
    return list(map(str, input().split()))


def error_print(*args):
    print(*args, file=sys.stderr)


def mt(f):
    import time

    def wrap(*args, **kwargs):
        s = time.time()
        ret = f(*args, **kwargs)
        e = time.time()

        error_print(e - s, 'sec')
        return ret

    return wrap


@mt
def slv(N, AB):
    
    t = []
    for a, b in AB:
        t.append((a+b, a, b))
    
    t.sort(reverse=True)
    A = 0
    B = 0
    for i, (_, a, b) in enumerate(t):
        if i % 2 == 0:
            A += a
        else:
            B += b
    return A- B


def main():
    N = read_int()
    AB = [read_int_n() for _ in range(N)]
    print(slv(N, AB))


if __name__ == '__main__':
    main()

Solution (Python):
N=int(input())
dinner=[]
for i in range(N):
    a,b=[int(j) for j in input().split(" ")]
    dinner.append([a,b])

dinner=sorted(dinner,key=lambda x:x[1]+x[0])
takahashi=0
aoki=0

while True:
    d=dinner.pop(-1)
    takahashi+=d[0]
    if len(dinner)==0:
        break
    d=dinner.pop(-1)
    aoki+=d[1]
    if len(dinner)==0:
        break

print(takahashi-aoki)

Solution (Python):


import sys
import heapq


INF = float('inf')
MOD = 10 ** 9 + 7

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 LS(): return sys.stdin.readline().split()
def II(): return int(sys.stdin.readline())
def SI(): return input()


n = II()
src = []
for i in range(n):
    a, b = LI()
    src.append((a + b, a, b))
src.sort()





score_a, score_b = 0, 0
for i in range(n):
    if i % 2:
        x, a, b = src.pop()
        score_b += b

    else:
        x, a, b = src.pop()
        score_a += a

print(score_a - score_b)

Solution (Python):
n = int(input())
ab = [list(map(int,input().split())) for i in range(n)]
c = [[ab[k][0] + ab[k][1], ab[k][0], ab[k][1]] for k in range(n)]
c.sort()
c.reverse()
taka = 0
aoki = 0
for i in range(n): 
    if i%2 ==0: 
        taka += c[i][1]
    else: 
        aoki += c[i][2]

print(taka - aoki)

Solution (Python):

n=int(input())
O=[]


for i in range(n):
    a,b=map(int, input().split(" "))
    O.append([a+b,a,b])
  

O=sorted(O, key=lambda x: (x[0]))[::-1]


count=0
for num in range(n):
    if num%2==0:
        count+=O[num][1]
    else:
        count-=O[num][2]

print(count)

Solution (Python):
n = int(input())
h = [[int(i) for i in input().split()] for j in range(n)]
s = [[h[i][0]+ h[i][1], i] for i in range(n)]
s.sort(reverse=True)
ans = 0
flag = 0
for i in range(n):
    if flag == 0:
        ans += h[s[i][1]][0]
        flag = 1
    else:
        ans -= h[s[i][1]][1]
        flag = 0
print(ans)

Solution (Python):
n = int(input())
info =[list(map(int,input().split())) for i in range(n)] 

diff = [[0] for i in range(n)]
sorted_diff = [[0] for i in range(n)]

for i in range(n):
  diff[i][0] = info[i][0]+info[i][1] 

for i in range(n):
  info[i].extend(diff[i])


sorted_diff = sorted(info, key=lambda x: x[2])


takahashi =0
aoki = 0
for i in range(n):
  if i%2==0:
    takahashi+= sorted_diff[-1][0]

    del sorted_diff[-1]
  else:
    aoki+=sorted_diff[-1][1]

    del sorted_diff[-1]
    
print(takahashi-aoki)

Solution (Python):
N = int(input())
A = []
B = []
S = {}

for i in range(N):
    Ai, Bi = map(int, input().split())
    A.append(Ai)
    B.append(Bi)
    S[i] = (Ai + Bi)

A_total = 0
B_total = 0
i = 0
for k, v in sorted(S.items(), key=lambda x: -x[1]):
    if i % 2 == 0:
        A_total += A[k]
    else:
        B_total += B[k]
    i += 1

print(A_total - B_total)

Solution (Python):
N = int(input())
ABlist = []

for n in range(N):
    a, b = input().split()
    a = int(a)
    b = int(b)
    winP = a + b
    ABlist.append((a, b, winP))

sortedList = sorted(ABlist, key=lambda x: x[2], reverse=True)


Acount = 0
Bcount = 0

for i,x in enumerate(sortedList):
    if i % 2 == 0:
        Acount = Acount + x[0]
    elif i % 2 == 1:
        Bcount = Bcount + x[1]

print(Acount - Bcount)

Solution (Python):
N = input()
A = [0]*N
B = [0]*N
for i in range(N):
  A[i],B[i] = map(int, raw_input().split())

T = []
for i in range(N):
  T += [(-A[i]-B[i], i)]
T.sort()

ans = 0
for i in range(N):
  if i%2==0:
    ans += A[T[i][1]]
  else:
    ans -= B[T[i][1]]
print ans

Solution (Python):
N = int(input())
A = [list(map(int,input().split())) for i in range(N)]

B = [[a[0],a[1],a[0]+a[1]] for a in A]
B = sorted(B, key=lambda x: x[2], reverse=True)
Taka=0
Aoki=0

for i, b in enumerate(B):
    if i%2==0:
        Taka+=b[0]
    else:
        Aoki+=b[1]
    

print(Taka-Aoki)

Solution (Python):
n=int(input())
absa=[]


for i in range(n):
    c=[]
    c=[int(j) for j in input().split()]
    absa.append([c[0],c[1],c[1]+c[0]])


from operator import itemgetter
absa.sort(key=itemgetter(2))

t=0
k=0
for i in range(n):
    if i%2==0:
        t+=absa[-1][0]
        del absa[-1]
    else:
        k+=absa[-1][1]
        del absa[-1]
    
    

print(t-k)

Solution (Python):
from sys import stdin
from itertools import repeat
def main():
    n = int(stdin.readline())
    dat = map(int, stdin.read().split(), repeat(10, 2 * n))
    s = sum(dat[::2])
    a = [dat[i*2] + dat[i*2+1] for i in xrange(n)]
    a.sort(reverse=True)
    print s - sum(a[1::2])
main()

Solution (Python):
l = []
c = int(input())
for i in range(c):
    a,b = map(int, input().split())
    l.append([a,b,abs(a+b)])
l.sort(key=lambda x:x[2])
k = l[::-1]
s = 0
for i in range(c):
    if i%2==0:
        s +=k[i][0]
    else:s-=k[i][1]
print(s)

Solution (Python):
n = int(input())
AB = [list(map(int, input().split())) for _ in range(n)]
AB.sort(reverse = True,key = lambda x:x[0]+x[1])
ans = 0
for i in range(n):
    if i % 2 == 0:
        ans += AB[i][0]
    else:
        ans -= AB[i][1]
print(ans)

Solution (Python):

n=int(input())
data=[]
for i in range(n):
    data.append(list(map(int,input().split())))
data=sorted(data,key=lambda x:-x[0]-x[1])
a=0
b=0
for i in range(n):
    if i%2==0:
        a+=data[i][0]
    else:
        b+=data[i][1]
print(a-b)

Solution (Python):
n = int(input())
Ascore = 0
Bscore = 0
A, B = [], []
for i in range(n):
    a, b = map(int, input().split())
    c = a + b
    A.append((a,b,c))
A.sort(key=lambda x:x[2], reverse=True)
Aturn = True
for a in A:
    if Aturn:
        Ascore += a[0]
        Aturn = False
    else:
        Bscore += a[1]
        Aturn = True
print(Ascore-Bscore)

Solution (Python):
N = int(input())
C = [list(map(int, input().split())) for _ in range(N)]
C = sorted(map(lambda x: ((x[0] + x[1]), x), C), reverse=True)



print(sum(c[1][0] for c in C[::2]) - sum(c[1][1] for c in C[1::2]))

Solution (Python):
N = int(input())
inputs = [list(map(int, input().split())) for _ in range(N)]

dicts = {}
for i in range(N):
    dicts[i] = sum(inputs[i])

t = 0
a = 0
count = 0
for key, value in sorted(dicts.items(), key=lambda x: -x[1]):
    if count % 2 == 0:
        t += inputs[key][0]
    else:
        a += inputs[key][1]
    count += 1

print(t - a)

Solution (Python):
def IL(): return list(map(int,input().split()))
def SL(): return input().split()
def I(): return int(input())
def S(): return input()
n=I()
dl=[]
taka=[]
aoki=[]
for i in range(n):
    a,b=IL()
    dl.append([i,a,b,a+b])
dl.sort(key=lambda x:-x[3])
t=1
ans=0
for i in range(n):
    if t==1:
        taka.append(i)
        t=-1
    else:
        aoki.append(i)
        t=1
for i in taka:
    ans+=dl[i][1]
for i in aoki:
    ans-=dl[i][2]
print(ans)

Solution (Python):
n = int(input())
a = []
b = []
a_b = []
count = 0
for i in range(n):
    c ,d = map(int, input().split())
    a.append(c)
    b.append(d)
    a_b.append((c+d,count))
    count += 1

count = 0
ans = 0
for i in sorted(a_b,reverse=True):
    if count % 2 == 0:
        ans += a[i[1]]
    else:
        ans -= b[i[1]]
    count += 1
print(ans)

Solution (Python):


import math
import sys
import itertools
import numpy as np

n =int(input())


ab = [[int(i) for i in input().split()] for i in range(n)] 



ab.sort(key = lambda x: -x[1]-x[0])

answer = 0
for i in range(n):
    if i % 2 == 0:
        answer += ab[i][0]
    else:
        answer -= ab[i][1]
print(answer)

Solution (Python):
n = int(input())

l = []

for _ in range(n):
    a,b = map(int, input().split())
    l.append((a+b,a,b))

l.sort()

ans = 0
for i in range(n):
    if i%2 == 0:
        ans += l[n-1-i][1]
    else:
        ans -= l[n-1-i][2]

print(ans)

Solution (Python):
N = int(input())
taka = []
aoki = []
sum_of_both = {}
for i in range(N):
    a, b = map(int, input().split())
    taka.append(a)
    aoki.append(b)
    sum_of_both[i] = a + b

p_taka = 0
p_aoki = 0
turn = 0
for k, v in sorted(sum_of_both.items(), key=lambda x: x[1], reverse=True):
    if turn % 2 == 0:
        p_taka += taka[k]
    else:
        p_aoki += aoki[k]
    turn += 1

print(p_taka - p_aoki)

Solution (Python):
l=[]
n=int(input())
for i in range(n):
  a,b=map(int,input().split())
  l.append((a,b,a+b))
l=sorted(l,key=lambda t: t[2],reverse=True)
x=y=0
for i in range(n):
  if i%2==0:
    x+=l[i][0]
  else:
    y+=l[i][1]
print(x-y)

Solution (Python):
n = int(input())
a = []
b = []
a_b = []
point_a = 0
point_b = 0
for i in range(n):
    tmp1 , tmp2 = map(int,input().split())
    a.append(tmp1)
    b.append(tmp2)
    a_b.append((tmp1+tmp2,i))
a_b.sort()
while a_b:
    point_a += a[a_b.pop(-1)[1]]
    if a_b:
        point_b += b[a_b.pop(-1)[1]]
    else:
        break
print(point_a - point_b)

Solution (Python):
from operator import itemgetter
N = int(input())
AB = [list(map(int, input().split(" "))) for i in range(N)]

ABC = [[a, b, a+b] for a, b in AB]
ABC = sorted(ABC, key=itemgetter(2), reverse=True)
ans = 0
flag = True
for a, b, c in ABC:
    if flag:
        ans += a
    else:
        ans -= b
    flag = not flag
print(ans)

Solution (Python):
N = int(input())
AB = [[] for i in range(N)]
for i in range(N):
    A, B = map(int, input().split())
    AB[i] = [A, B, A+B]

AB.sort(key=lambda x:x[2], reverse=True)

ta = 0
for i in range(N):
    if i % 2 == 0:
        ta += AB[i][0]
    else:
        ta -= AB[i][1]
print(ta)

Solution (Python):
import numpy as np
n = int(input())
takahashi_u = []
aoki_u = []
sum_u = []
takahashi_eat = []
aoki_eat = []
for i in range(n):
  a, b = map(int, input().split())
  takahashi_u.append(a)
  aoki_u.append(b)
  sum_u.append(a+b)
arr = np.array([sum_u, takahashi_u, aoki_u])
sort_index = np.argsort(arr[0])[::-1]
sort_arr = arr[:, sort_index]
takahashi_arr = sort_arr[1, 0::2]
aoki_arr = sort_arr[2, 1::2]
print(sum(takahashi_arr) - sum(aoki_arr))

Solution (Python):
n = int(input())
li = []

for i in range(n):
    a,b = map(int,input().split())
    c = a+b
    li.append([a,b,c])

li.sort(key=lambda x:x[2],reverse=True)

takahashi = 0
aoki = 0
for i in range(n):
    if i%2 == 0:
        takahashi += li[i][0]
    else:
        aoki += li[i][1]

print(takahashi-aoki)

Solution (Python):

N = int(input())


AB = [list(map(int,input().split())) for _ in range(N)]

ans = 0

P = [[0,0,0] for _ in range(N)]

for i in range(N):
    P[i][0] = AB[i][0] + AB[i][1]
    P[i][1] = AB[i][0]
    P[i][2] = AB[i][1]

P.sort()
P.reverse()

for i in range(N):
    if (i % 2 == 0):
        ans += P[i][1]
    else:
        ans -= P[i][2]
    
    
    
    
    
    
    
    
    
    

print(ans)

Solution (Python):
import numpy as np
n = int(input())
a = []
b = []
c = []
for i in range(n):
  a_i, b_i = map(int,input().split())
  a.append(a_i)
  b.append(b_i)
  c.append(a_i+b_i)
c.sort(reverse=True)
k = int((n+1)/2)
print(np.sum(c[::2])-np.sum(b))

Solution (Python):
N = int(input())
arr = []
for i in range(N):
    a,b = list(map(int, input().split()))
    arr.append([a,b])
arr = sorted(arr, key=lambda x: x[0]+x[1], reverse=True)
ans = 0
for i in range(N):
    if i%2 == 0:
        ans += arr[i][0]
    else:
        ans -= arr[i][1]
print(ans)

Solution (Python):
from string import ascii_lowercase
def inpl(): return list(map(int, input().split()))
tkao = [0, 0]
t = 0

N = int(input())
A = [0]*N
B = [0]*N
for i in range(N):
    A[i], B[i] = inpl()
C = [A, B]

S = sorted([((B[i] + A[i]), i) for i in range(N)], key=lambda x: x[0])

for i in range(N):
    tkao[i%2] += C[i%2][S.pop()[1]]

print(tkao[0] - tkao[1])

Solution (Python):
N = int(input())
AB = [[int(i) for i in input().split()] for _ in range(N)]
C = [0]*N
tk = 0
ao = 0
for i in range(N):
    C[i] = (sum(AB[i]),i)
for i,j in enumerate(sorted(C)[::-1]):
    tmp = j[1]
    if i % 2 == 0:
        tk+=AB[tmp][0]
    else:
        ao+=AB[tmp][1]
print(tk-ao)

Solution (Python):
from math import ceil
N = int(input())
b = []
c = []

for i in range(N):
    A,B = map(int,input().split())
    b.append(B)
    c.append(-1*(A+B))

c.sort()
ans = 0 
for i in range(ceil(N/2)):
    ans -= c[2*i]

ans -= sum(b)
print(ans)

Solution (Python):
n=int(input())
lst=[list(map(int, input().split())) for i in range(n)]
lst.sort(key=lambda x: -x[0]-x[1])
ans=0
for i in range(n):
  if(i%2==0):
    ans+=lst[i][0]
  else:
    ans-=lst[i][1]
print(ans)

Solution (Python):
n = int(input())
a = [0 for _ in range(n)]
b = [0 for _ in range(n)]
cost = [[0, 0] for _ in range(n)]
for i in range(n):
    a[i], b[i] = [int(i) for i in input().split()]
    cost[i] = [a[i]+b[i], i]

cost.sort()
cost.reverse()
scoreA = 0
scoreB = 0
for i in range(len(cost)):
    if i % 2 == 0:
        scoreA += a[cost[i][1]]
    else:
        scoreB += b[cost[i][1]]
print(scoreA -scoreB)

Solution (Python):
N=int(input())
dish=[]
for i in range(N):
  a,b=map(int,input().split())
  dish.append([a,b])
d2=sorted(dish,key=lambda x:-x[1]-x[0])
ans=0
for i in range(0,N,2):
  ans+=d2[i][0]
for i in range(1,N,2):
  ans-=d2[i][1]
print(ans)

Solution (Python):
import collections

def solve():
    N = int(input())
    A = []
    B = []
    for i in range(N):
        (a, b) = [int(x) for x in input().split()]
        A.append(a)
        B.append(b)

    pq = sorted([(a,b) for a, b in zip(A, B)], key=lambda x: sum(x))
    pq = collections.deque(pq)
    

    score = [0, 0]
    idx = 0
    while pq:
        x = pq.pop()
        score[idx] += x[idx]
        idx = (idx + 1) % 2
    

    return score[0] - score[1]


def main():
    ans = solve()
    print(ans)


if __name__ == '__main__':
    main()

Solution (Python):
n = int(input())
Point_ti = []
Sa = 0
Sb = 0
for _ in range(n):
    a, b = map(int, input().split())
    Sa += a
    Sb += b
    Point_ti.append(a+b)

Point_ti.sort(reverse=True)
ans = 0
for i in range(n):
    if i%2 == 0:
        ans += Point_ti[i]
print(ans-Sb)

Solution (Python):
N = int(input())
P = [list(map(int, input().split())) for _ in range(N)]

P = sorted(P, key=lambda p: - p[0] - p[1])

ret = 0

for i, p in enumerate(P):
    if i % 2 == 0:
        ret += p[0]
    else:
        ret -= p[1]

print(ret)

Solution (Python):
N = int(input())
A = []
B = []
dam = []
for i in range(N):
    aa,bb = (int(i) for i in input().split())
    A.append(aa)
    B.append(bb) 
    dam.append((i,aa+bb))

dam = sorted(dam, key=lambda x: x[1], reverse=True)
aok = dam[0::2]
tak = dam[1::2]

asum = 0
for i in aok:
    asum = asum + A[i[0]]

bsum = 0
for i in tak:
    bsum = bsum + B[i[0]]

print(asum - bsum)

Solution (Python):
def main():
    n = int(input())
    points = []
    for i in range(n):
        a, b = map(int, input().split())
        points.append((a, b, a + b))

    
    points = sorted(points, key=lambda x: x[2], reverse=True)
    

    t = 0
    a = 0
    for i, p in enumerate(points):
        if i == 0 or i % 2 == 0:
            t += p[0]
        else:
            a += p[1]

    print(t - a)


if __name__ == '__main__':
    main()

Solution (Python):
def getN():
    return int(input())

def getMN():
    a = input().split()
    b = [int(i) for i in a]
    return b[0],b[1]

def getlist():
    a = input().split()
    b = [int(i) for i in a]
    return b

dishes = []
n = getN()
for i in range(n):
    dishes.append(getMN())

dishes.sort(key=lambda x: -(x[0] + x[1]))

ans = 0
for i, d in enumerate(dishes):
    if i % 2 == 0:
        ans += d[0]
    else:
        ans -= d[1]

print(ans)

Solution (Python):
import numpy as np
N = int(input())
AB = []
for i in range(N):
    AB.append(list(map(int,input().split())))
AB = np.array(AB)
scores = np.argsort(np.sum(AB,axis=1))[::-1]

ascore = AB[scores[0::2]][:,0].sum()
bscore = AB[scores[1::2]][:,1].sum()
print(ascore-bscore)

Solution (Python):
n = int(input())
a,b = [],[]
lisC = []
for i in range(n):
    tmp = list(int(i) for i in input().split())
    a.append(tmp[0])
    b.append(tmp[1])
    lisC.append((sum(tmp),i))
lisC = sorted(lisC)
res = 0
for i in range(n):
    if i%2==0:
        res += a[lisC[n-1-i][1]]
    else:
        res -= b[lisC[n-1-i][1]]
print(res)

Solution (Python):
N = int(input())
L = []
for _ in range(N):
    a, b = map(int, input().split())
    L.append((a, b, a+b))
L.sort(key=lambda x:x[2])


score = 0
while True:
    if not L:
        break
    score += L.pop()[0]
    if not L:
        break
    score -= L.pop()[1]
print(score)

Solution (Python):
N = int(input())
happy = [tuple(map(int, input().split())) for _ in range(N)]
happy.sort(key=lambda x: x[0] + x[1])
result = [0, 0]
for i, x in enumerate(reversed(happy)):
    result[i % 2] += x[i % 2]
print(result[0] - result[1])

Solution (Python):
N=int(input())
W=[]
for i in range(N):
    A,B=map(int,input().split())
    W.append((A+B,A,B))
W.sort(key= lambda x:x[0],reverse=True)

isTakahashiTurn=True
score=0
for i in range(N):
    if isTakahashiTurn:
        score+=W[i][1]
        isTakahashiTurn=False
    else:
        score-=W[i][2]
        isTakahashiTurn=True
print(score)