#include<iostream>
#include<cstring>
using namespace std;
bool mojing(string s,int end)//end下标
{
	bool f;
	if((end+1)%2==0){
		f=true;
		for(int i=0;i<=end/2;i++){
			if(s[i]!=s[end-i]){
				f=false;
				break;
			}
		}
	} 
	else{
		f=false;
	}
	return f;
 } 
int main(){
	string s;
	cin>>s;
	int end=s.size()-1;
	while(mojing(s,end)==true){//满足镜面要求一直循环 
		end=end/2;
	} 
	cout<<end+1; 
	return 0;
}