#include <bits/stdc++.h>
using namespace std;
int n;
int main() {
  ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  cin >> n;
  if (n == 1) {
    cout << 'a' << endl;
  } else if (n == 2) {
    cout << "aa" << endl << "ab" << endl;
  } else if (n == 3) {
    cout << "aaa" << endl << "aab" << endl << "abb" << endl << "abc" << endl;
  } else if (n == 4) {
    cout << "aaaa" << endl
         << "aaab" << endl
         << "aabb" << endl
         << "abbb" << endl
         << "abbc" << endl
         << "abcc" << endl
         << "abcd" << endl;
  }
  return 0;
}
