#coding: utf-8
##yuki_273
import sys

def palindrome(string): return 1 if string==string[::-1] else 0

s=raw_input()
n=len(s)

if n==2 and s[0]==s[1]:
 print 1
 sys.exit()

res=0
for i in xrange(n):
 for j in xrange(n):
  if palindrome(s[i:n-j])==1:
   res_temp=len(s[i:n-j])
   if res_temp>res:
    res=res_temp

if res==n:
 print res-2
else:
 print res