#include <bits/stdc++.h>
using namespace std;
const long long int M = 1000003;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int k;
  cin >> k;
  string s = "codeforces";
  vector<long long int> count(10);
  for (long long int i = 0; i < 10; i++) count[i] = 1;
  long long int ans = 1;
  long long int i = 0;
  while (1) {
    if (ans >= k) break;
    if (i == 10) i = 0;
    ans = ans / count[i];
    count[i] += 1;
    ans *= count[i];
    i++;
  }
  for (int i = 0; i < 10; i++) {
    for (int j = 0; j < count[i]; j++) cout << s[i];
  }
}
