#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int n;
  cin >> n;

  int x = 1;
  while (x + 1 + (x+1) * x / 2 <= n) ++x;

  n -= x + x * (x-1) / 2;
  string ret(x, 'a');
  string t = "bcdef";
  REP (i, n)
    ret += t[i%5];

  cout << ret << endl;
  
  return 0;
}