#include <bits/stdc++.h>
using namespace std;
int N;
int main() {
  cin >> N;
  for (int i = 0; i < 1 << N - 1; i++) {
    string now = "a";
    for (int j = 0; j < N - 1; j++) now += i >> N - 2 - j & 1 ? 'b' : 'a';
    cout << now << endl;
  }
}
