#include <bits/stdc++.h>
void solve() {
  std::string cdf = "codeforces";
  int count[10] = {};
  for (int i = 0; i < 10; ++i) {
    count[i] = 1;
  }
  unsigned long long k;
  std::cin >> k;
  unsigned long long subs = 1;
  int i = 0;
  while (subs < k) {
    subs /= count[i];
    count[i]++;
    subs *= count[i];
    i = (i + 1) % 10;
  }
  for (int i = 0; i < cdf.size(); ++i) {
    while (count[i]--) {
      std::cout << cdf[i];
    }
  }
  return;
}
void warp() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(0);
  std::cout.tie(0);
}
int main() {
  warp();
  solve();
}
