#!/usr/bin/python
# -*- coding: utf-8 -*-

inp = raw_input()
palin_max = 1

for i in range(len(inp)): #回文の起点
    for j in range(i+palin_max, len(inp)): #回文の終点
        target = inp[i:j+1]
        if target[:(j-i)/2+1] == target[:(j-i-1)/2:-1]:
            palin_max = len(target)
            #print target, palin_max

if palin_max == len(inp): 
    if len(set(inp))==1:#全部同じ
        palin_max -= 1
    else: #左右対称
        palin_max -= 2

print palin_max