#include <bits/stdc++.h>
using namespace std;
const string S = "codeforces";
int main() {
  long long k;
  cin >> k;
  long long freq[10];
  for (int i = 0; i < 10; i++) freq[i] = 1;
  int id = 0;
  while (true) {
    long long prod = 1;
    for (int i = 0; i < 10; i++) prod *= freq[i];
    if (prod >= k) break;
    freq[id]++;
    id = (id + 1) % 10;
  }
  for (int i = 0; i < 10; i++)
    for (int r = 0; r < freq[i]; r++) cout << S.at(i);
  cout << "\n";
}
