#include <bits/stdc++.h>
using namespace std;
int main(int argc, char const *argv[]) {
  string s = "codeforces";
  vector<long long> a(10, 1);
  long long k, cur = 1, idx = 0;
  scanf("%lld", &k);
  while (cur < k) {
    cur = (cur / a[idx]) * (a[idx] + 1);
    a[idx]++;
    idx++;
    idx %= 10;
  }
  for (int i = 0; i < 10; ++i) {
    while (a[i]--) printf("%c", s[i]);
  }
  return 0;
}
