#include <bits/stdc++.h>
int main() {
  long long k;
  std::cin >> k;
  const char s[] = "codeforces";
  unsigned int v[10];
  for (unsigned int i = 0; i < 10; ++i) v[i] = 1;
  long long p = 1;
  while (p < k) {
    for (unsigned int i = 0; i < 10; ++i) {
      ++v[i];
      p /= (v[i] - 1);
      p *= v[i];
      if (p >= k) break;
    }
  }
  for (unsigned int i = 0; i < 10; ++i) {
    while (v[i]--) {
      printf("%c", s[i]);
    }
  }
  return 0;
}
