#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define rep(i, s, e) for (int(i) = (s); (i) <= (e); (i)++)
int main() {
  i64 N;
  cin >> N;
  i64 K = 0;
  string all = "qwertyuiopasdfghjklzxcvbnm";
  int idx = 0;
  string ans = "qwqw";
  if (N == 1) {
    cout << "a" << endl;
    return 0;
  }
  int i = 40;
  while (!(N & (1LL << i)))
    i--;
  i--;
  idx = 2;
  bool first = true;
  for (; i >= 0; i--) {
    if (!first) {
      ans = ans[0] + ans;
      ans = ans + ans[0];
    }
    first = false;
    if (N & (1LL << i)) {
      ans = string() + all[idx] + ans + all[idx];
      idx++;
      if(idx >= all.size()){
        idx = 0;
        random_shuffle(all.begin(),all.end());
      }
    }
  }
  cout << ans << endl;
}