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