#include<bits/stdc++.h>

using namespace std;

bool cek(char a) {
    if (int(a) >= 97 && int(a) <= 122) return false;
    return true;
}

int main() {
    int n, hitung = 0;
    string kata, temp, test;

    cin >> n;

    getline(cin, test);
    getline(cin, kata);

    char a,b,c;
    a = kata[0];
    b = kata[1];
    c = kata[2];

    for (int i=3;i<=n;i++) {
        if (a == 'h' && b == 'h' && c == 'h') {
            hitung++;
        }

        if (cek(a) || cek(b) || cek(c)) {
            n = -1;
            break;
        }

        a = kata[i-2];
        b = kata[i-1];
        c = kata[i];
    }

    if (n == kata.length()) cout << hitung << endl;
    else if (n < 3 || n > 100) cout << 0 << endl;
    else cout << 0 << endl;
}