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

/**************************************************************
	Problem: 1134
	User: zzz
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2076 kb
****************************************************************/