#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
const int MOD = 1000000007;
const ll INF = 1e18;
const long double EPS = 1e-9;
const long double PI = acos(-1);
void solve() {
  ll k;
  cin >> k;
  vector<ll> vec(10, 1);
  ll cur = 1;
  int idx = 0;
  while (cur < k) {
    cur /= vec[idx % 10];
    ++vec[idx % 10];
    cur *= vec[idx % 10];
    ++idx;
  }
  string s = {"codeforces"};
  for (int i = 0; i < 10; ++i) {
    cout << string(vec[i], s[i]);
  }
  cout << '\n';
  return;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int t_num = 1;
  while (t_num--) {
    solve();
  }
  return 0;
}
