#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  string cf = "codeforces";
  vector<int> cnt(cf.length(), 1);
  int64_t k;
  cin >> k;
  int64_t ps = 1;
  int64_t i = 0;
  while (ps < k) {
    ps = ps / cnt[i] * (cnt[i] + 1);
    cnt[i]++;
    i = (i + 1) % cf.length();
  }
  string res;
  for (int i = 0; i < cf.length(); i++) {
    for (int j = 0; j < cnt[i]; j++) {
      res += cf[i];
    }
  }
  cout << res << endl;
  return 0;
}
