#include<bits/stdc++.h>
using namespace std;
string s;
int a; 
int main(){
   cin>>s;
   a=s.size();
   for(int i=0;i<s.size();i++){
   	if(s[i]==s[a-i-1]){
   		a=a/2;
   	}
    s.substr(0,a)=s;

   }
   cout<<a;
   return 0;
}

/**************************************************************
	Problem: 1134
	User: chenjingqi
	Language: C++
	Result: Wrong Answer
****************************************************************/