#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
int main() {
  string N;
  cin >> N;
  char last = N.back();
  if (last == '3') {
    cout << "bon" << endl;
  } else if (last == '0' || last == '1' || last == '6' || last == '8') {
    cout << "pon" << endl;
  } else {
    cout << "bon" << endl;
  }
  return 0;
}
