#include<bits/stdc++.h>
using namespace std;
bool hw(string s){
	bool r=true;
	for(int i=0;i<=s.size()/2;i++){
		if(s[i]!=s[s.size()-i-1]){
			r=false;
		}
	}
	return r;
}
int main(){
	string s;
	cin>>s;
	int n=s.size();
	if(!hw(s)){
		cout<<n;
	} 
    else{
    	while(n!=0){
       		if(hw(s)){
          	n=n/2; 
       		}
     		s=s.substr(0,n);
    	if(!hw(s)){
    		break;
    	}  
   	}
    cout<<s.size();
     
   } 
	return 0;
}

/**************************************************************
	Problem: 1134
	User: xuanhua
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2076 kb
****************************************************************/