#include <bits/stdc++.h>
using namespace std;
long long k, doSad;
const string cf = "codeforces";
int niz[10];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> k;
  if (k == 1) {
    cout << cf;
    return 0;
  }
  for (int i = 0; i < 10; ++i) niz[i] = 1;
  doSad = 1;
  bool preko = false;
  while (true) {
    for (int i = 0; i < 10; ++i) {
      doSad /= niz[i]++;
      doSad *= niz[i];
      if (doSad >= k) {
        preko = true;
        break;
      }
    }
    if (preko) break;
  }
  for (int i = 0; i < 10; ++i) {
    cout << string(niz[i], cf[i]);
  }
  return 0;
}
