# -*- coding: utf-8 -*-
def ch(S):
    N = len(S)
    SR = S[:]
    SR.reverse()
    if S == SR:
        return N
    else:
        return 0


S = list(raw_input())
N = len(S)
cntmax = 0
if len(S) == 2:
    print 1
    exit()
for i in range(0, N-1):
    for j in range(i+1, N+1):
        tmp = ch(S[i:j])
        if cntmax < tmp:
            cntmax = tmp
print cntmax