#include <bits/stdc++.h>
using namespace std;
int main() {
  long long unsigned int k, a, b, c[10], i, j;
  cin >> k;
  for (i = 0; i < 10; i++) {
    c[i] = 1;
  }
  a = 1;
  i = 0;
  while (a < k) {
    a = a / c[i];
    c[i] = c[i] + 1;
    a = a * c[i];
    i = (i + 1) % 10;
  }
  string m = "codeforces";
  string res;
  for (i = 0; i < 10; i++) {
    for (j = 0; j < c[i]; j++) {
      res = res + m[i];
    }
  }
  cout << res << endl;
}
