#include <bits/stdc++.h>
using namespace std;
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int k;
	cin>>k;
	string s;
	cin>>s;
	int n = s.length();
	int N[n];
	N[0] = 0;
	for(int i = 1;i < n;++i) {
		int p = N[i - 1];
		while(p != 0 && s[p] != s[i]){
			p = N[p - 1];
		}
		if(s[p] == s[i]) {
			p++;
		}
		N[i] = p;
	}
	long long ans = 0;
	for(int i = n - 1;i >= 0;--i) {
		int j = N[i];
		if(j == 0) continue;
		while(N[j - 1]) j = N[j - 1];
		N[i] = j;
		ans += i - j + 1;
	}
	cout<<ans;
	return 0;
}