#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long int k;
  cin >> k;
  vector<int> a(10, 1);
  long long int prod = 1;
  int i = 0;
  while (true) {
    i %= 10;
    if (prod >= k) break;
    a[i]++;
    prod = prod * a[i] / (a[i] - 1);
    i++;
  }
  string s = "codeforces";
  for (int i = 0; i < 10; i++) cout << string(a[i], s[i]);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  int t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
