#include <bits/stdc++.h>
using namespace std;
int main() {
  long long k;
  cin >> k;
  const string s = "codeforces";
  const int n = s.size();
  vector<long long> counts(n, 1);
  long long p = 1;
  int cur = 0;
  while (p < k) {
    p = p / counts[cur] * (counts[cur] + 1);
    ++counts[cur];
    cur = (cur + 1) % n;
  }
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < counts[i]; ++j) cout << s[i];
  }
  cout << "\n";
  return 0;
}
