#coding: utf-8
##yuki_273

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

s=raw_input()
n=len(s)

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

print res