def is_palindrome(word):
    for i in range(len(word)//2):
        if word[i] != word[-i-1]:
            return False
    return True

S = input()
a = 1
for l in range(2, len(S)):
    for i in range(len(S)-l+1):
        if is_palindrome(S[i:i+l]):
            a = l
            break
print(a)