#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  ll k;
  cin >> k;
  vector<int> freq(10, 1);
  ll cur = 1;
  while (cur < k) {
    int ndx = min_element(freq.begin(), freq.end()) - freq.begin();
    cur /= freq[ndx];
    ++freq[ndx];
    cur *= freq[ndx];
  }
  string ans = "codeforces";
  for (int i = 0; i < 10; ++i) {
    cout << string(freq[i], ans[i]);
  }
  cout << "\n";
}
