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