#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long k, i, j, b = 1;
  string s = "codeforces";
  vector<int> a(10, 1);
  cin >> k;
  for (; b < k;)
    for (i = 0; i < 10; i++) {
      b /= a[i];
      ++a[i];
      b = b * a[i];
      if (b > k - 1) break;
    }
  for (i = 0; i < 10; i++)
    for (j = 0; j < a[i]; j++) cout << s[i];
  cout << "\n";
  return;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long t = 1;
  while (t--) solve();
}
