Harryxun/sft_time huggingface dataset:
### BUGGY CODE ###

# https://beta.atcoder.jp/contests/arc098/tasks/arc098_a
# C - Attention

# C_Attention.py

N = int(input())
S = input()

#e = [0 for i in range(N)]
#w = [0 for i in range(N)]
d = [0 for i in range(N)]
#print("累積和")

for i in range(N):
    # そこからE側の人で、Wを向くべきなのにEを向いている人
    if S[i] == "E":
        for j in range(0, i):
            #e[j]+=1
            d[j]+=1
    # そこからW側の人で、Eを向くべきなのにWを向いている人
    else:
        for j in range(i+1, N):
            #w[j]+=1
            d[j]+=1
    #print("i:", i)
    #print("w:", w)
    #print("e:", e)
    #print("")

#w[0] = 0
#e[-1] = 0

#print("w:", w)
#print("e:", e)
min = 10 ** 6

for i in range(N):
    if d[i] < min:
        min = d[i]
print(min)


### FIXED CODE ###

# https://beta.atcoder.jp/contests/arc098/tasks/arc098_a
# C - Attention

# C_Attention.py

N = int(input())
S = input()

e = [0 for i in range(N)]
w = [0 for i in range(N)]
d = [0 for i in range(N)]
#print("累積和")

for i in range(N):
    # そこからE側の人で、Wを向くべきなのにEを向いている人
    #if S[i] == "E":
    #    for j in range(0, i):
    #        e[j]+=1
    #        d[j]+=1
    # そこからW側の人で、Eを向くべきなのにWを向いている人
    if i > 0:
        w[i] += w[i-1]
    if i < N-1:
        if S[i] == "W":
            w[i+1] += 1
    if i > 0:
        e[N-1-i] += e[N-1-(i-1)]
    if i < N-1:
        if S[N-1-i] == "E":
            e[N-1-(i+1)] += 1

    #print("i:", i)
    #print("w:", w)
    #print("e:", e)
    #print("")

#w[0] = 0
#e[-1] = 0

#print("w:", w)
#print("e:", e)
min = 10 ** 6
for i in range(N):
    total = e[i] + w[i]
    if total < min:
        min = total
print(min)
### BUGGY CODE ###

from sys import stdin
def main():
    n = int(stdin.readline().rstrip())
    a = list(map(int,stdin.readline().rstrip().split()))
    mod = 10**9+7
    point = 0
    kai = [2**i%mod for i in range(61)]
    for i in range(61):
        now = sum(1 for j in a if(j >> i)&1)
        point += now*(n-now)*kai[i]
        point %= mod
    print(point)
if __name__ == "__main__":
    main()

### FIXED CODE ###

n = int(input())
a = list(map(int,input().split()))
mod = 10**9+7
point = 0
for i in range(61):
    now = 0
    for j in a:
        now += (j >> i&1)
    now *= n-now
    now %= mod
    for k in range(i):
        now *= 2
        now %= mod
    point += now
    point %= mod
print(point)
### BUGGY CODE ###

s = input()
q = int(input())
q_lists = [input().split() for _ in range(q)]
hanten = 0
for i in q_lists:
    if len(i)==1:
        hanten += 1
    else:
        f = i[1]
        c = i[2]
        if hanten%2==0:
            if f=='1':
                s = c + s
            else:
                s = s + c
        else:
            if f=="1":
                s = s + c
            else:
                s = c + s
print(s if hanten%2==0 else s[::-1])        

### FIXED CODE ###

s = input()
q = int(input())
ans_list1 = []
ans_list2 = []
flag = 1
for i in range(q):
    i = input().split()
    if i[0]=="1":
        flag *= -1
    else:
        if i[1]=='1':
            if flag==1:
                ans_list1.append(i[2])
            else:
                ans_list2.append(i[2])
        else:
            if flag==1:
                ans_list2.append(i[2])
            else:
                ans_list1.append(i[2])

if flag==1:
    print(''.join(ans_list1[::-1]) + s +''.join(ans_list2))
else:
    print(''.join(ans_list2[::-1]) + s[::-1] +''.join(ans_list1))
### BUGGY CODE ###

import math
K=int(input())
ans=0
for a in range(1,K+1):
  for b in range(1,K+1):
    for c in range(1,K+1):
      gcd=math.gcd(a,b)
      gcd=math.gcd(gcd,c)
      ans+=gcd
print(ans)

### FIXED CODE ###

import math
K=int(input())
ans=0
for a in range(1,K+1):
  for b in range(1,K+1):
    for c in range(1,K+1):
      gcd=math.gcd(a,b)
      gcd=math.gcd(gcd,c)
      ans+=gcd
print(ans)
### BUGGY CODE ###

n,m=map(int,input().split())
h = list(map(int, input().split()))
bad = []
ans =[]

for i in range(m):
    a,b=map(int,input().split())
    if h[a-1] > h[b-1]:
        bad.append(b)
    elif h[a-1] == h[b-1]:
        bad.append(a)
        bad.append(b)
    else:
        bad.append(a)

j = 1
for j in range(n+1):
    if j in bad:
        pass
    else:
        ans.append(j)
    j += 1
        
print(len(ans)-1)

### FIXED CODE ###

n,m=map(int,input().split())
h = list(map(int, input().split()))
bad = []

for i in range(m):
    a,b=map(int,input().split())
    if h[a-1] > h[b-1]:
        bad.append(b)
    elif h[a-1] == h[b-1]:
        bad.append(a)
        bad.append(b)
    else:
        bad.append(a)

bad_two = set(bad)
ans = n - len(bad_two)
print(ans)
### BUGGY CODE ###

n, k = map(int, input().split())
p = list(map(int, input().split()))

m = 0
for i in range(n-k+1):
  tmp = sum(p[i:i+k])
  if tmp > m :
    m = tmp
print((m + k)/2)

### FIXED CODE ###

import itertools

n, k = list(map(int, input().split()))
p = list(map(int, input().split()))

pa = list(itertools.accumulate([0] + p))

m = 0
for i in range(n-k+1):
  s = pa[i+k] - pa[i]
  if s > m:
    m = s
print((m+k)/2)
### BUGGY CODE ###

def intersect_list(lst1, lst2):
    arr = []
    lst = lst1.copy()
    for element in lst2:
        try:
            lst.remove(element)
        except ValueError:
            pass
        else:
            arr.append(element)
    return len(arr)

n=int(input())
a=[list(input()) for i in range(n)]
count=0
for i in range(len(a)):
    for j in range(i+1,len(a)):
        if intersect_list(a[i],a[j])==len(a[i]):
            count+=1
print(count)

### FIXED CODE ###

import math
import collections

n=int(input())
a=[list(input()) for i in range(n)]
b=[str(sorted(list(i))) for i in a]
count=list(collections.Counter(b).values())
count=[i for i in count if i>1]
print(int(sum([math.factorial(x)/(math.factorial(x-2)*2) for x in count])))
### BUGGY CODE ###

n, k = [int(i) for i in input().split()]
r, s, p = [int(i) for i in input().split()]
t = input()
ans = 0
dic = {'p': s, 's': r, 'r': p}
for i in range(k):
  ans += dic[t[i]]
dic_ls = []
for i in range(k, n):
  if t[i] != t[i - k] or (i - k) in dic_ls:
    ans += dic[t[i]]
  else:
    dic_ls.append(i)
print(ans)

### FIXED CODE ###

n, k = [int(i) for i in input().split()]
r, s, p = [int(i) for i in input().split()]
t = list(input())
ans = 0
dic = {'p': s, 's': r, 'r': p}
for i in range(k):
  ans += dic[t[i]]
dic_ls = []
for i in range(k, n):
  if t[i] != t[i - k]:
    ans += dic[t[i]]
  else:
    t[i] = 'j'
print(ans)
### BUGGY CODE ###

N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))
A.sort()
B.sort()
C.sort()
ans = 0
def func(array, value):
  ng = -1
  ok = len(array)
  #if value
  while ok - ng > 1:
    mid = (ok + ng)//2
    if array[mid] < value:
      ng = mid
    elif array[mid] >= value:
      ok = mid
  return ok
for a in A:
  b_idx = func(B, a + 1)
  if b_idx == len(B):
    break
  #print('a', a)
  #print('B[b_idx:]',B[b_idx:])
  for b in B[b_idx:]:
    c_idx = func(C, b + 1)
    #print('b',b)
    #print('C[c_idx:]',C[c_idx:])
    if c_idx == len(C):
      break
    #print(a, b_idx, c_idx)
    ans += len(C) - c_idx
print(ans)

### FIXED CODE ###

N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))
A.sort()
B.sort()
C.sort()
ans = 0
def low_func(array, value):
  ng = -1
  ok = len(array)
  #if value
  while ok - ng > 1:
    mid = (ok + ng)//2
    if array[mid] < value:
      ng = mid
    elif array[mid] >= value:
      ok = mid
  return ok

def up_func(array, value):
  ok = -1
  ng = len(array)
  #if value
  while abs(ok - ng) > 1:
    mid = (ok + ng)//2
    if array[mid] <= value:
      ok = mid
    elif array[mid] > value:
      ng = mid
  return ok

for b in B:
  a_idx = up_func(A, b - 1)
  if a_idx == -1:
    continue
  c_idx = low_func(C, b + 1)
  if c_idx == len(C):
    break
  ans += (a_idx + 1)*(len(C) - c_idx)
print(ans)
### BUGGY CODE ###

N, K = map(int, input().split())
A = [False]*(N+1)
for _ in range(K):
    l, r = map(int, input().split())
    for a in range(l, r+1):
        A[a] = True

S = []
for i in range(1,N+1):
    if A[i]:
        S.append(i)
        
mod = 998244353
        
table = [0]*N
table[0] = 1

for i in range(N):
    for s in S:
        if i + s < N:
            table[i+s] += table[i]
            table[i+s] %= mod
            
print(table[N-1]%mod)

### FIXED CODE ###

N, K = map(int, input().split())
S = []
for _ in range(K):
    l, r = map(int, input().split())
    S.append((l, r))

mod = 998244353
        
table = [0]*N
table[0] = 1
TABLE = [0]*N
TABLE[0] = 1

for i in range(1, N):
    TABLE[i] = TABLE[i-1]
    for L, R in S:
        l = i-L
        r = i-R-1
        if r >= 0:
            table[i] += TABLE[l] - TABLE[r]
            table[i] %= mod
            TABLE[i] += TABLE[l] - TABLE[r]
            TABLE[i] %= mod
        elif l >= 0 and r < 0:
            table[i] += TABLE[l]
            table[i] %= mod
            TABLE[i] += TABLE[l]
            TABLE[i] %= mod
            
print(table[N-1]%mod)
### BUGGY CODE ###

from collections import deque
N = int(input())
*P, = map(int, input().split())
MOD = 10**9 + 7

G = [[] for i in range(N+1)]
for i, p in enumerate(P):
    G[p].append(i+1)
Q = [None]*(N+1)
for i in range(N, -1, -1):
    # i+1 <- P[i]
    Q[i] = q = deque([[1, 1, 0, 1]])
    R = []
    for j in G[i]:
        R.append(Q[j])

    if R:
        R.sort(key=len, reverse=1)

        last = R.pop()
        while R:
            nxt = R.pop()
            for k in range(len(nxt)):
                if last:
                    a0, a1, a2, c0 = last.popleft()
                    b0, b1, b2, c1 = nxt.popleft()
                    C = [a0*b0 % MOD, (a0*b1 + a1*b0) % MOD, (a0*b2 + a1*b1 + a2*b0 + a1*b2 + a2*b2 + a2*b1) % MOD, c0+c1]
                    nxt.append(C)
                else:
                    nxt.append(nxt.popleft())
            last = nxt
        # a0 <- a2
        for e in last:
            e[0] += e[2]
            e[2] = 0
        q.extend(last)
ans = 0
for a0, a1, a2, c in Q[0]:
    ans += pow(2, N+1-c, MOD) * a1 % MOD
print(ans % MOD)

### FIXED CODE ###

# seishin.py
from collections import deque
N = int(input())
*P, = map(int, input().split())
MOD = 10**9 + 7

G = [[] for i in range(N+1)]
U = [0]*(N+1)
C = [0]*(N+1)
for i, p in enumerate(P):
    G[p].append(i+1)
    U[i+1] = u = U[p]+1
    C[u] += 1
Q = [None]*(N+1)
PP = {}
def pp(k):
    if k not in PP:
        PP[k] = p = pow(2, k, MOD)
        return p
    return PP[k]
L = [0]*(N+1)

ept = []
sz = L.__getitem__
for i in range(N, -1, -1):
    g = G[i]
    if not g:
        continue

    # 子ノードのdequeを集める
    g.sort(key=sz, reverse=1)
    k = len(g)
    e = [pp(k) - k, k, 0]

    g0 = g[0]
    L[i] = L[g0] + 1
    if L[g0] == 0:
        Q[i] = deque([e])
        continue
    Q[i] = R = Q[g0]
    if k > 1:
        # a0 <- a2
        for s, r in zip(Q[g[1]] or ept, R):
            r[0] += r[2]; r[2] = 0

        for j in g[1:]:
            S = Q[j]
            if not S:
                break

            # dequeの小さい方から大きい方へマージする処理
            for (a0, a1, a2), r in zip(S, R):
                b0, b1, b2 = r; a0 += a2
                r[0] = a0*b0 % MOD
                r[1] = (a0*b1 + a1*b0) % MOD
                r[2] = ((a0+a1)*b2 + a1*b1) % MOD
    R.appendleft(e)
print((pp(N) + sum(pp(N+1-c) * a1 % MOD for (a0, a1, a2), c in zip(Q[0], C[1:]))) % MOD)
### BUGGY CODE ###

N, M = map(int, input().strip().split(" "))

edge = []

for m in range(M):
    a, b = map(int, input().strip().split(" "))
    edge.append((a,b))

to_one = [False] * N
to_N = [False] * N

for n in range(N):
     to_one[n] = len([e for e in edge if e[0] == 1 and e[1] == n]) > 0
     to_N[n] = len([e for e in edge if e[0] == n and e[1] == N]) > 0

res = False
for n in range(N):
    if to_one[n] and to_N[n]:
        print("POSSIBLE")
        res = True
        break

if not res:
    print("IMPOSSIBLE")

### FIXED CODE ###

N, M = map(int, input().strip().split(" "))

to_one = [False] * N
to_N = [False] * N
for m in range(M):
    a, b = map(int, input().strip().split(" "))
    if a == 1:
        to_one[b] = True
    if b == N:
        to_N[a] = True

res = False
for n in range(2, N):
    if to_N[n] and to_one[n]:
        print("POSSIBLE")
        res = True
        break

if not res:
    print("IMPOSSIBLE")
### BUGGY CODE ###

from collections import defaultdict
n = int(input())
r = []
for i in range(n):
    x, l = map(int, input().split())
    r.append((x - l + 1, x + l - 1))
r.sort()
am = [[] for _ in range(n)]
for i in range(n):
    for j in range(i + 1, n):
        if r[i][1] >= r[j][0]:
            am[i].append(j)
            am[j].append(i)
while sum(len(mi) for mi in am):
    maxi, maxd = 0, 0
    for i, mi in enumerate(am):
        li = len(mi)
        if li > maxd:
            maxi, maxd = i, li
    for pi in am[maxi]:
        am[pi].remove(maxi)
    am.pop(maxi)
    n -= 1
print(n)

### FIXED CODE ###

n = int(input())
r = []
for i in range(n):
    x, l = map(int, input().split())
    r.append((x - l, x + l))
r.sort(key=lambda _x: _x[1])
cnt = 1
limit = r[0][1]
for ri in r[1:]:
    if ri[0] >= limit:
        cnt += 1
        limit = ri[1]
print(cnt)
### BUGGY CODE ###

from collections import Counter
n=int(input())
a=list(map(int,input().split()))
b=list(map(int,input().split()))
#n=pow(10,4)
#a=[2]*(n//2)+[3]*(n//2)
#b=[1]*(n//2)+[2]*(n//2)
ca=Counter(a)
cb=Counter(b)
for k in cb:
    if k in ca:
        if cb[k]+ca[k]>n:
            print('No')
            exit()
ans=b[n//2:]+b[:n//2]
ng=set(())
ok=[]
for i in range(n):
    if a[i]==ans[i]:
        ng.add(i)
    else:
        ok.append(i)
from random import randint
while ng:
    k=len(ng)
    nng=set(())
    l=len(ok)
    i=0
    for x in ng:
        i+=1
        y=ok[randint(0,l-1)]
        ans[x],ans[y]=ans[y],ans[x]
        if ans[x]==a[x] or ans[y]==a[y]:
            ans[x],ans[y]=ans[y],ans[x]
            nng.add(x)
        else:
            ok.append(x)
    ng=nng

print('Yes')
print(*ans,sep=' ')


### FIXED CODE ###

from collections import Counter
n=int(input())
a=list(map(int,input().split()))
b=list(map(int,input().split()))
ca=Counter(a)
cb=Counter(b)
for k in cb:
    if k in ca:
        if cb[k]+ca[k]>n:
            print('No')
            exit()
tmpc=0
tmpd=0
c=[0]
d=[0]
for i in range(1,n+1):
    if i in ca:tmpc+=ca[i]
    if i in cb:tmpd+=cb[i]
    c.append(tmpc)
    d.append(tmpd)
x=0
for i in range(n+1):
    x=max(x,c[i]-d[i-1])
ans=b[-x:]+b[:-x]
print('Yes')
print(*ans,sep=' ')
exit()
print(c)
print(d)
### BUGGY CODE ###

K, S = map(int, input().split())
ans = 0
for X in range(min(K, S)+1):
    for Y in range(min(K, S)+1):
        if 0 <= S-X-Y <= min(K, S):
            ans += 1 
print(ans)

### FIXED CODE ###

K, S = map(int, input().split())
ans = 0
for X in range(min(K, S)+1):
    for Y in range(min(K, S-X)+1):
        if 0 <= S-X-Y <= K:
            ans += 1 
print(ans)
### BUGGY CODE ###

def factorial(num):
    if num < 0:
        return 0
    result = 1
    for x in range(num, 0, -2):
        result *= x
    return result

def count_zero(num):
    a = str(factorial(num))
    i = len(a)-1
    count = 0
    while(i > 0):
        if(int(a[i]) == 0):
            count += 1
        else:
            break
        i -= 1
    return count

n = int(input())
print(count_zero(n))


### FIXED CODE ###

# v=[]
# num=251
# for i in range(num):
#     if i==0 or i==1:
#         v.append(1)
#     else:
#         v.append(i*v[i-2])
        
# for i in range(0,num,2):
#     print(i,v[i],end=' ')
#     print()

n=int(input())
if n%2!=0:
    print(0)
else:
    ans=n//10
    n=n//10
    i=1
    while(1):
        ans+=n//(5**i)
        if n//(5**i)==0:
            break
        i+=1
        
        
    print(ans)
### BUGGY CODE ###

T,A,K = map(int,input().split())
for i in range(K):
    if T > 0:
        T -= 1
    elif A > 0:
        A -= 1
print(str(T) + " " + str(A))   

### FIXED CODE ###

T,A,K = map(int,input().split())
sta = T + A - K
if sta <= 0:
    print("0 0")
elif sta >= A:
    print(str(T-K) +" "+str(A))
else:
    print("0 " + str(sta))
### BUGGY CODE ###

# -*- coding: utf-8 -*-
import sys
import math
from bisect import bisect_left
from bisect import bisect_right
import collections
import copy
input = sys.stdin.readline
 
# bisect_left(lists, 3)
# bisect_right(lists, 3)
 
def main():
	N, M = map(int, input().split(" "))
	#N = int(input())
	#S = input()

	LR = []
	min_i = -1
	max_i = -1
	for i in range(M):
		L, R = map(int, input().split(" "))
		LR.append((L, R))
		if i == 0:
			min_i = L
			max_i = R
		else:
			if L < min_i:
				min_i = L
			if max_i < R:
				max_i = R

	ans = 0
	for i in range(min_i, max_i+1):
		flg = True
		for j in LR:
			L, R = j

			if i <= R and i >= L:
				flg = True
			else:
				flg = False
				break
		if flg == True:
			#print("sss")
			ans += 1

	print(ans)


if __name__ == "__main__":
	main()

### FIXED CODE ###

# -*- coding: utf-8 -*-
import sys
import math
from bisect import bisect_left
from bisect import bisect_right
import collections
import copy
input = sys.stdin.readline
 
# bisect_left(lists, 3)
# bisect_right(lists, 3)
 
def main():
	N, M = map(int, input().split(" "))
	#N = int(input())
	#S = input()

	LR = []
	min_i = -1
	max_i = -1
	min_a = -1
	max_a = -1
	for i in range(M):
		L, R = map(int, input().split(" "))
		LR.append((L, R))
		if i == 0:
			min_i = L
			max_i = R
			min_a = L
			max_a = R
		else:
			if L > min_i:
				min_i = L
			if max_i > R:
				max_i = R

	ans = 0
	for i in range(min_i, max_i+1):
		ans += 1

	print(ans)


if __name__ == "__main__":
	main()
### BUGGY CODE ###

K, S = map(int, input().split())

# print(K)
# print(S)

count = 0
for i in range(K + 1):
	for j in range(K + 1):
		for k in range(K + 1):
			if i + j + k == S:
				count += 1

print(count)

### FIXED CODE ###

K, S = map(int, input().split())

# print(K)
# print(S)

count = 0
for i in range(K + 1):
	for j in range(K + 1):
		# for k in range(K + 1):
		# 	if i + j + k == S:
		# 		count += 1
		if i + j <= S and i + j + K >= S:
			count += 1

print(count)
### BUGGY CODE ###

#13:19
n = int(input())
s = input()
t = []
for i in range(n):
  t.append(ord(s[i])-97)
q = int(input())
seg = [[0 for _ in range(2**20)] for _ in range(26)]
for i in range(n):
  tmp = int(i) + 2**19
  x = t[i]
  while tmp != 0:
    seg[x][tmp] += 1
    tmp //= 2
#print(seg)
raw = []
for _ in range(q):
  d,a,b = input().split()
  d = int(d)
  if d == 1:
    a = int(a) - 1
    b = ord(b) - 97
  else:
    a = int(a) - 2
    b = int(b) - 1
  raw.append([d,a,b])
for p in range(q):
  d,a,b = raw[p]
  if d == 1:
    tmp = int(a)
    c = t[tmp]
    tmp += 2**19
    while tmp != 0:
      seg[c][tmp] -= 1
      tmp //= 2
    tmp = int(a)
    t[tmp] = b
    tmp += 2**19
    while tmp != 0:
      seg[b][tmp] += 1
      tmp //= 2
  else:
    ans = 0
    for d in range(26):
      l = 0
      r = 0
      if a == -1:
        l = 0
      else:
        tmp = a + 2**19
        l += seg[d][tmp]
        while tmp != 1:
          if tmp % 2 == 1:
            l += seg[d][tmp-1]
          tmp //= 2
      tmp = b + 2**19
      r += seg[d][tmp]
      while tmp != 1:
        if tmp % 2 == 1:
          r += seg[d][tmp-1]
        tmp //= 2
      if r > l:
        ans += 1
      #print(d,r,l)
    print(ans)
#print(t)

### FIXED CODE ###

#13:19
n = int(input())
s = input()
t = []
for i in range(n):
  t.append(ord(s[i])-97)
q = int(input())
scale = 19
seg = [[0 for _ in range(2**(scale+1))] for _ in range(26)]
for i in range(n):
  tmp = int(i) + 2 ** scale
  x = t[i]
  while tmp != 0:
    seg[x][tmp] += 1
    tmp //= 2
#print(seg)
raw = []
for _ in range(q):
  d,a,b = input().split()
  d = int(d)
  if d == 1:
    a = int(a) - 1
    b = ord(b) - 97
  else:
    a = int(a) - 2
    b = int(b) - 1
  raw.append([d,a,b])
for p in range(q):
  d,a,b = raw[p]
  if d == 1:
    tmp = int(a)
    c = t[tmp]
    tmp += 2**scale
    while tmp != 0:
      seg[c][tmp] -= 1
      tmp >>= 1
    tmp = int(a)
    t[tmp] = b
    tmp += 2**scale
    while tmp != 0:
      seg[b][tmp] += 1
      tmp >>= 1
  else:
    ans = 0
    for d in range(26):
      l = 0
      r = 0
      if a == -1:
        l = 0
      else:
        tmp = a + 2**scale
        l += seg[d][tmp]
        while tmp != 1:
          if tmp & 1:
            l += seg[d][tmp-1]
          tmp >>= 1
      tmp = b + 2**scale
      r += seg[d][tmp]
      while tmp != 1:
        if tmp & 1:
          r += seg[d][tmp-1]
        tmp >>= 1
      if r > l:
        ans += 1
      #print(d,r,l)
    print(ans)
#print(t)
### BUGGY CODE ###

n = int(input())
b = [''.join(sorted(input())) for i in range(n)]
c = list(set(b))
ans = 0
for i in c:
  d = b.count(i)
  if d >1:
    ans += d*(d-1)//2
print(ans)

### FIXED CODE ###

N = int(input())
s_sort = [''.join(sorted(input())) for _ in range(N)]
dic = {}
ans = 0
for i in s_sort:
  if i not in dic:
    dic[i] = 0
  else:
    dic[i] += 1
    ans += dic[i]
print(ans)
### BUGGY CODE ###

N = int(input())
A = list(map(int,input().split()))
d = N // 2
ans = []
def linking_up():
    for i in range(N):
        if i % 2 == 0 and i != 0:
            if A.count(i) == 2 and A.count(0) == 1:
                ans.append('c')
            else:
                ans.append('b')
        else:
            if A.count(i) == 2:
                ans.append('a')
            else:
                ans.append('b')
linking_up()
if ans.count('a') == d or ans.count('c')== d:
    print(2 ** d)
else:
    print(0)
        




### FIXED CODE ###

n=int(input())
a=list(map(int,input().split()))
a.sort()
mod=10**9+7
if n%2==0:
  for i in range(n):
    if a[i]!=(i//2)*2+1:
      print(0)
      exit()
  print(pow(2,n//2,mod))
else:
  for i in range(n):
    if a[i]!=((i+1)//2)*2:
      print(0)
      exit()
  print(pow(2,n//2,mod))
### BUGGY CODE ###

import sys
input = lambda : sys.stdin.readline().rstrip()

from heapq import heappush, heappop 

running = []
events = []
delete = set()

n, q = map(int, input().split())
for _ in range(n):
    s, t, x = map(int, input().split())
    time = max(s - x, 0)
    if t - x < 0:
        continue
    events.append((s - x, x, 1)) # 追加イベント
    events.append((t - x, x, 0)) # 削除イベント
events.sort()
ans = []
idx = -1
for _ in range(q):
    d = int(input())
    if d >= events[-1][0]:
        print(-1)
        #ans.append(-1)
        continue
    while events[idx + 1][0] <= d:
        idx += 1
        if events[idx][2] == 1:
            heappush(running, events[idx][1])
            delete.discard(events[idx][1])
        else:
            delete.add(events[idx][1])
    flag = 1
    while running:
        x = heappop(running)
        if x not in delete:
            heappush(running, x)
            print(x)
            #ans.append(x)
            flag = 0
            break
    if flag:
        print(-1)
        #ans.append(-1)

### FIXED CODE ###

import sys
input = lambda : sys.stdin.readline().rstrip()

from heapq import heappush, heappop 

running = []
events = []
delete = set()

n, q = map(int, input().split())
for _ in range(n):
    s, t, x = map(int, input().split())
    time = max(s - x, 0)
    if t - x < 0:
        continue
    events.append((s - x, x, 1)) # 追加イベント
    events.append((t - x, x, 0)) # 削除イベント
events.sort()
ans = []
idx = -1
for _ in range(q):
    d = int(input())
    if d >= events[-1][0]:
        print(-1)
        #ans.append(-1)
        continue
    while events[idx + 1][0] <= d:
        idx += 1
        if events[idx][2] == 1:
            heappush(running, events[idx][1])
            delete.discard(events[idx][1])
        else:
            delete.add(events[idx][1])
    flag = 1
    while running:
        x = heappop(running)
        if x not in delete:
            heappush(running, x)
            print(x)
            #ans.append(x)
            flag = 0
            break
    if flag:
        print(-1)
### BUGGY CODE ###

n,*a=map(int,open(0).read().split())
dp=[[0]*(n+1) for _ in range(n+1)]
for l in range(n)[::-1]:
	for r in range(n)[::-1]:
		if l+r<=n-1:
			dp[l][r]=max(a[l]-dp[l+1][r],a[n-1-r]-dp[l][r+1])
print(dp[0][0])

### FIXED CODE ###

n,*a=map(int,open(0).read().split())
dp=[[0]*(n+1) for _ in range(n+1)]
for l in range(n)[::-1]:
	for r in range(n)[::-1]:
		if l+r<=n-1:
			dp[l][r]=max(a[l]-dp[l+1][r],a[n-1-r]-dp[l][r+1])
print(dp[0][0])