#include <bits/stdc++.h>
using namespace std;
int main() {
  long long k;
  cin >> k;
  int A[10] = {};
  for (int i = 0; i < 10; i++) A[i] = 1;
  long long pro = 1;
  int i = 0;
  while (pro < k) {
    pro /= A[i];
    A[i]++;
    pro *= A[i];
    if (i == 9)
      i = 0;
    else
      i++;
  }
  string s = "codeforces";
  for (int i = 0; i < 10; i++) cout << string(A[i], s[i]);
  cout << "\n";
  return 0;
}
