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

S = input()
N = len(S)
ans = 1
for length in range(N-1, 1, -1):
    for p in range(N-length+1):
        if ispalindrome(S[p:p+length]):
            ans = length
            break
    else:
        continue
    break
print(ans)