#include<iostream>
#include<string>
using namespace std;

int main() {
    string s;
    cin >> s;
    int res = 0;
    int pain = s.find("pain");
    if (pain != -1) {
        for (int i = 0; i < pain; i++) {
            if (s[i] == 'p' && s[i + 1] == 'o' && s[i + 2] == 'n') {
                res++;
            }
        }
        if (res > 1) cout << res - 1 << endl;
        else cout << -1 << endl;
    }
    else cout << -1 << endl;
}