#include <bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
void y_k() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
int32_t main() {
  y_k();
  long long k;
  cin >> k;
  string str = "codeforces";
  long long val[11];
  for (long long i = 0; i < 11; i++) val[i] = 1;
  long long prod = 1;
  while (prod < k) {
    for (long long i = 0; i < 10; i++) {
      val[i]++;
      prod = prod / (val[i] - 1);
      prod = prod * (val[i]);
      if (prod >= k) break;
    }
  }
  for (long long i = 0; i < 10; i++) {
    while (val[i]) {
      cout << str[i];
      val[i]--;
    }
  }
  cout << "\n";
  return 0;
}
