#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  string cf = "codeforces";
  long long k;
  cin >> k;
  vector<long long> a(10, 1);
  long long i = 0;
  long long p = 1;
  while (p < k) {
    p = p / a[i] * (a[i] + 1);
    a[i]++;
    i = (i + 1) % 10;
  }
  for (long long j = 0; j < 10; j++) {
    cout << string(a[j], cf[j]);
  }
  return 0;
}
