#include <bits/stdc++.h>
using namespace std;
using LL = long long;
int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  LL k;
  cin >> k;
  string cf = "codeforces";
  int n = cf.size();
  vector<int> a(n, 1);
  LL prod = 1;
  for (int i = 0; prod < k; i = (i + 1) % n) {
    prod = prod / a[i] * (a[i] + 1);
    ++a[i];
  }
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < a[i]; ++j) {
      cout << cf[i];
    }
  }
  cout << endl;
  return 0;
}
