#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int k;
  cin >> k;
  long long int arr[11];
  for (long long int i = 0; i <= 10; i++) arr[i] = 1;
  long long int temp = 1;
  long long int i = 1;
  while (temp < k) {
    temp /= arr[i];
    arr[i]++;
    temp *= arr[i];
    i++;
    if (i > 10) i = 1;
  }
  string s = " codeforces";
  for (long long int i = 1; i <= 10; i++) {
    for (long long int j = 1; j <= arr[i]; j++) {
      cout << s[i];
    }
  }
  cout << "\n";
}
