#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 9;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  long long int n;
  int a[10];
  string s = "codeforces";
  cin >> n;
  long long int p = 1, ans = 0;
  int pos = 0;
  for (int i = 0; i < 10; i++) a[i] = 1;
  while (p < n) {
    p = p / a[pos];
    a[pos]++;
    p = p * a[pos];
    pos++;
    pos = pos % 10;
  }
  for (int i = 0; i < 10; i++) {
    cout << string(a[i], s[i]);
  }
}
