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