#include<fstream>
#include<iostream>
#include<cstring>
#define N 1000001
using namespace std;
char s[N];
int prefix[N];
void calcul_prefix(char s[]){
	int n=strlen(s),i,j;
	prefix[0]=-1;
	for(i=1;i<n;i++){
		j=prefix[i-1];
		if(s[i]==s[j+1])
			prefix[i]=j+1;
		else{
			while(j>=0 && s[i]!=s[j+1])
				j=prefix[j];
			if(s[i]==s[j+1])
				prefix[i]=j+1;
			else
				prefix[i]=-1; //=j	
			/*
			if(s[i]==s[j+1])
				j++;
			prefix[i]=j;	
			*/
		}	
	}
	 
}
int prefix_periodic(char s[]){
	calcul_prefix(s);
	int n=strlen(s);
	while(n>=0){
		if(prefix[n-1]!=-1){
			int t= n-(prefix[n-1]+1);
			if (n%t==0)
				return n;
			
		}
		n--;
	}
	return -1;
}
int main(){
	 
	ifstream f("prefix.in");
	ofstream g("prefix.out");
	f.getline(s,N);
	while(f.getline(s,N)){
		int x=prefix_periodic(s);
		if(x!=-1)
			g<<x<<endl;
		else
			g<<-1<<endl;	
			
	}
	g.close();
	
}