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

int main() {
    string s;
    cin >> s;
    int n = s.size();
    int pon = 0;
    bool pain = false;
    for(int i=0;i<n;i++) {
        if(s[i] == 'p') {
            if(i + 2 < n && s[i+1] == 'o' && s[i+2] == 'n') {
                pon++;
            }
            if(i + 3 < n && s[i+1] == 'a' && s[i+2] == 'i' && s[i+3] == 'n') {
                pain = true;
                break;
            }
        }
    }

    int out = 0;

    if(!pain || pon < 2) out = -1;
    else out = pon - 1;

    cout << out << '\n';
}