#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long int n;
  cin >> n;
  string s = "";
  for (long long int i = 0; i < n; i++) s += "a";
  cout << s << '\n';
  for (long long int i = n - 1; i >= 1; i--) {
    string t = s;
    for (long long int j = i; j < n; j++) {
      t[j] = 'b';
      cout << t << '\n';
    }
  }
  return 0;
}
