#include<iostream>
	#include<cstring>
	#define ll long long
	using namespace std;
	const int N = 1e6+7;
	int l;
	string n;
	ll ne[N];
	int main()
	{
		cin>>l;
		cin>>n;
		for(ll i = 1,j = 0; i < l;i++){
			while(j > 0&& n[i] != n[j])j = ne[j - 1];
			if(n[i] == n[j])j++;
			ne[i] = j;
		}
         cout<<l-ne[l - 1];
	    return 0;
	}