#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000000 + 7;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long k;
  cin >> k;
  string s = "codeforces";
  long long num = 1, r = 1;
  while (num < k) {
    r++;
    num = 1;
    for (int i = 0; i < 10; i++) num = num * r;
  }
  if (num > k) r--;
  num = 1;
  for (int i = 0; i < 10; i++) num = num * r;
  for (int i = 0; i < s.size(); i++) {
    if (num < k) {
      num /= r;
      num = num * (r + 1);
      for (int j = 0; j < r + 1; j++) cout << s[i];
    } else {
      for (int j = 0; j < r; j++) cout << s[i];
    }
  }
  cout << endl;
  return 0;
}
