#include <bits/stdc++.h>
using namespace std;
void out_char(int num, string s, char c) {
  if (s.length() >= num) {
    cout << s << endl;
    return;
  }
  char next_c = c++;
  string c_now = {c};
  string c_next = {next_c};
  out_char(num, s + c_now, c);
  out_char(num, s + c_next, next_c);
}
int main() {
  int n;
  cin >> n;
  out_char(n, "a", 'a');
}
