#include <bits/stdc++.h>
using namespace std;
long long k;
long long mpow(long long a, long long n) {
  if (n == 0) return 1;
  long long r = mpow(a, n / 2);
  r *= r;
  if (n % 2) r *= a;
  return r;
}
int main() {
  cin >> k;
  string s0 = "codeforces";
  string res = "";
  for (long long l = 10; l <= 400; l++) {
    long long n0 = (l - 10) / 10 + 1;
    long long n1 = l - n0 * 10;
    vector<long long> ns(10, n0);
    for (int i = 0; i < n1; i++) {
      ns[i]++;
    }
    long long cur = 1;
    for (int i = 0; i < 10; i++) {
      cur *= ns[i];
    }
    if (cur >= k) {
      for (int i = 0; i < 10; i++) {
        for (int j = 0; j < ns[i]; j++) {
          res.push_back(s0[i]);
        }
      }
      break;
    }
  }
  cout << res << endl;
  return 0;
}
