#include <bits/stdc++.h>
using namespace std;
int main() {
  char cuv[] = "codeforces";
  unsigned long long k, p;
  cin >> k;
  int i, c[10], j;
  for (i = 0; i < 10; i++) c[i] = 1;
  p = 1;
  i = 0;
  while (p < k) {
    p = p / c[i] * (c[i] + 1);
    c[i]++;
    i = (i + 1) % 10;
  }
  for (i = 0; i < 10; i++)
    for (j = 1; j <= c[i]; j++) cout << cuv[i];
  return 0;
}
