import sys
from functools import lru_cache
from itertools import permutations

def debug(x, table):
    for name, val in table.items():
        if x is val:
            print('DEBUG:{} -> {}'.format(name, val), file=sys.stderr)
            return None

def is_kaibun(S):
    return S == S[::-1]

def solve():
    S = input()
    n = len(S)
    ans = 1

    for i in range(n):
        for j in range(i + 1, n):
            if i == 0 and j == n - 1:
                continue

            if is_kaibun(S[i:j + 1]):
                # print(S[i:j + 1])
                ans = max(ans, j - i + 1)

    print(ans)

if __name__ == '__main__':
    solve()