#include <bits/stdc++.h>
using namespace std;
const long long int MOD = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int T;
  T = 1;
  while (T--) {
    long long int k, A[100], p, i, sum = 0, t;
    cin >> k;
    string s = "codeforces";
    for (i = 0; i < 10; i++) {
      A[i] = 1;
    }
    p = 1;
    i = 0;
    sum = 10;
    while (1) {
      if (p >= k) {
        break;
      }
      p = (p / A[i]) * (A[i] + 1);
      A[i] = A[i] + 1;
      sum++;
      i = (i + 1) % 10;
    }
    for (i = 0; i <= 9; i++) {
      t = A[i];
      while (t--) {
        cout << s[i];
      }
    }
  }
  return 0;
}
