import itertools

S = input()

is_palindrome = lambda S: S[:len(S) // 2] == S[-1:(-len(S) - 1) // 2:-1]

ans = 1
for i, j in itertools.combinations(range(len(S) + 1), 2):
    if is_palindrome(S[i:j]):
        ans = max(ans, j - i)
print(max(min(ans, len(S) - 2), 1))