S = input().strip()
def check(s):
    n = len(s)
    for i in range(n):
        if s[i] != s[n-i-1]:
            return False
    return True

r = 0 
N = len(S)
for i in range(1, N):
    if check(S[:i]):
        r = max(r, i)
    if check(S[i:]):
        r = max(r, N-i)
print(r)