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

S = raw_input()
L = len(S)
for i in range(L-1, 0, -1):
    for j in range(L-i+1):
        if is_palindrome(S[j:j+i]):
            print(i)
            quit()