#include <bits/stdc++.h>
using namespace std;
using vl = vector<long long>;
using pl = pair<long long, long long>;
using ll = long long int;
using vb = vector<bool>;
using vs = vector<string>;
using vvl = vector<vector<ll>>;
void read(vector<ll> &v, ll &n) {
  for (ll i = 0; i < n; ++i) cin >> v[i];
}
void write(vl &v) {
  for (ll i = 0; i < v.size(); ++i) cout << v[i] << " ";
  cout << endl;
}
void print() { cout << endl; }
void solve() {
  ll k;
  cin >> k;
  ll c = 1;
  vl v(11, 1);
  while (c < k) {
    for (ll i = 1; i < 11; i++) {
      c /= v[i];
      ++v[i];
      c *= v[i];
      if (c >= k) break;
    }
  }
  string s = "codeforces", res = "";
  for (ll i = 1; i < 11; i++) {
    while (v[i]--) {
      res.push_back(s[i - 1]);
    }
  }
  cout << res << endl;
  return;
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  ;
  solve();
  return 0;
}
