S = input()
N = len(S)

ans = 0
for i in range(1, N):
    if S[:i] == S[:i][::-1]:
        ans = max(ans, i)
for st in range(1, N):
    for i in range(1, N - st + 1):
        if S[st:st + i] == S[st:st + i][::-1]:
            ans = max(ans, i)
print(ans)