#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  vector<long long int> arr(10, 1);
  long long int k;
  cin >> k;
  long long int f = 0;
  long long int count = 1;
  while (1) {
    if (count >= k) {
      break;
    }
    for (long long int i = 0; i < 10; i++) {
      count /= arr[i];
      arr[i] += 1;
      count *= arr[i];
      if (count >= k) {
        f = 1;
        break;
      }
    }
    if (f) {
      break;
    }
  }
  string s = "codeforces";
  for (long long int i = 0; i < 10; i++) {
    for (long long int j = 0; j < arr[i]; j++) {
      cout << s[i];
    }
  }
  return 0;
}
