#include <bits/stdc++.h>
using namespace std;
const long long N = 2e6 + 7;
const long long INF = 1e18;
long long n, m, k, T;
string var = "codeforces";
long long fp(long long a, long long b) {
  if (b == 0) return 1;
  long long t = fp(a, b / 2);
  return (b & 1 ? t * t * a : t * t);
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  T = 1;
  cin >> n;
  long long l = 1, r = 78;
  while (l < r) {
    long long mid = l + (r - l) / 2;
    if (fp(mid, 10) > n)
      r = mid;
    else
      l = mid + 1;
  }
  r--;
  long long cur = fp(r, 10), cnt = 0;
  while (cur < n) {
    cur /= r;
    cur *= (r + 1);
    cnt++;
  }
  string ans;
  long long d = r;
  for (long long i = 0; i < 10; i++) {
    if (i == 10 - cnt) d++;
    for (long long j = 1; j <= d; j++) ans += var[i];
  }
  cout << ans << endl;
}
