#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string S(n, 'a');
  cout << S << endl;
  char c = 'a';
  for (int i = 0; i < n; i++) {
    c++;
    for (int j = n - 1; j > i; j--) {
      S[j] = c;
      cout << S << endl;
    }
  }
}
