#include <bits/stdc++.h>
using namespace std;
long long k, a[20];
char s[20] = "codeforces";
void init() { scanf("%lld", &k); }
bool check(int mid) {
  long long res = 1;
  for (int i = 1; i <= 10; i++) res *= mid;
  return res <= k;
}
void print() {
  for (int i = 1; i <= 10; i++)
    for (int j = 1; j <= a[i]; j++) printf("%c", s[i - 1]);
}
void work() {
  long long l = 1, r = 40, mid;
  while (l <= r) {
    mid = l + r >> 1;
    if (check(mid))
      l = mid + 1;
    else
      r = mid - 1;
  }
  for (int i = 1; i <= 10; i++) a[i] = r;
  long long now = 1;
  for (int i = 1; i <= 10; i++) now *= r;
  for (int i = 1; i <= 10; i++) {
    if (now >= k) {
      print();
      return;
    }
    now += now / a[i];
    a[i]++;
  }
  if (now >= k) print();
}
int main() {
  init();
  work();
  return 0;
}
