#include <bits/stdc++.h>
using namespace std;

int main(){
    int N;
    string S, T = "HAPPY";
    cin >> N >> S;

    int ans = 0;
    for (int i = 0; i < 5; i++){
        ans += (S[N-5+i] != T[i]);
    }

    for (int i = 0; i+5 <= N-5; i++){
        if (S.substr(i, 5) == T){
            ans++;
        }
    }

    cout << ans << endl;
}