#include <bits/stdc++.h>
using namespace std;
const long long M = 1e9 + 7;
void inp(long long a[], long long n) {
  for (long long i = 0; i < n; i++) cin >> a[i];
}
long long power(long long b, long long e) {
  if (e == 0) return 1;
  if (e & 1) return b * power(b * b, e / 2);
  return power(b * b, e / 2);
}
void solve() {
  long long n, k, l;
  cin >> n;
  string s = "codeforces";
  for (long long i = 1; i < 100; i++) {
    if (n < power(i, 10)) {
      k = i - 1;
      break;
    }
  }
  if (n == power(k, 10)) {
    l = 0;
  } else {
    for (long long i = 1; i < 10; i++) {
      long long x = power(k, 10 - i) * power(k + 1, i);
      if (x >= n) {
        l = i;
        break;
      }
    }
  }
  for (long long i = 0; i < (long long)((s).size()); i++) {
    long long x = k;
    if (l > 0) {
      x++;
      l--;
    }
    for (long long j = 0; j < x; j++) cout << s[i];
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t = 1;
  while (t--) solve();
}
