#include <bits/stdc++.h>
using namespace std;
int main() {
  long long k;
  cin >> k;
  vector<long long> v(10, 1);
  long long pro = 1;
  string s = "codeforces";
  for (int i = 0; pro < k; i = (i + 1) % 10) {
    pro = (pro / v[i]) * (v[i] + 1);
    v[i]++;
  }
  for (int i = 0; i < 10; i++) {
    for (int j = 0; j < v[i]; j++) {
      cout << s[i];
    }
  }
}
