def is_palindrome(s):
    n = len(s)
    if s == s[::-1]:
        return True
    else:
        return False

S = input()
N = len(S)

max_lenght = 0
for lenght in range(N - 1, 0, -1):
    for i in range(N - lenght):
        if is_palindrome(S[i:i + lenght]):
            print(lenght)
            exit()