#!/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)

if palin_max == len(inp): #全部同じ文字
    palin_max -= 1

print palin_max