#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
int main() {
  ll k;
  cin >> k;
  ll p = 1;
  map<int, int> m;
  for (int i = 0; i < 10; i++) m[i] = 1;
  string s = "codeforces";
  map<int, char> m2;
  for (int i = 0; i < s.length(); i++) {
    m2[i] = s[i];
  }
  while (p < k) {
    for (int i = 0; i < 10; i++) {
      p /= m[i];
      m[i]++;
      p *= m[i];
      if (p >= k) break;
    }
  }
  for (int i = 0; i < 10; i++) {
    for (int j = 0; j < m[i]; j++) cout << m2[i];
  }
}
