#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
  if (b == 0) {
    return (a);
  }
  return (gcd(b, a % b));
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  string s = "codeforces";
  long long k;
  cin >> k;
  long long ind = 0;
  long long cnt = 1;
  long long ans[10];
  for (long long i = 0; i < 10; i++) {
    ans[i] = 1;
  }
  while (cnt < k) {
    cnt = (cnt / ans[ind]) * (ans[ind] + 1);
    ans[ind]++;
    ind = (ind + 1) % 10;
  }
  for (long long i = 0; i < 10; i++) {
    for (long long j = 0; j < ans[i]; j++) {
      cout << s[i];
    }
  }
}
