#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long double k;
  cin >> k;
  int p = 0, q = 0;
  if (k == 1) {
    cout << "codeforces";
    return 0;
  }
  for (int i = 2;; i++) {
    if (k / (pow(i, 10)) < 1) {
      p = i;
      break;
    } else if (k / (pow(i, 10)) == 1) {
      q = i;
      break;
    }
  }
  string second = "codeforces";
  int x;
  if (p > 0) {
    for (int i = 1;; i++) {
      if (pow(p, i) * pow(p - 1, 10 - i) >= k) {
        x = i;
        break;
      }
    }
    for (int i = 0; i < x; i++) {
      int y = p;
      while (y--) cout << second[i];
    }
    int j = p - 1;
    for (int i = x; i < second.length(); i++) {
      int y = j;
      while (y--) cout << second[i];
    }
  } else if (q > 0) {
    for (int i = 0; i < second.length(); i++) {
      int y = q;
      while (y--) cout << second[i];
    }
  }
}
