#include<bits/stdc++.h>
using namespace std;
int ss(string n,int m){
	for(int i=0;i<m/2;i++){
		if(n[i]!=n[m-i-1]) return 0;
	}
	return 1;
}
int main(){
	int i;
	string a;
	getline(cin,a);
	int l=a.size();
	while(ss(a,l)==1){
		l/=2;	
	}
	cout<<l;
return 0;}

/**************************************************************
	Problem: 1134
	User: fzy001
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2076 kb
****************************************************************/