#include <bits/stdc++.h>
using namespace std;
using namespace std;
const int MAXN = 2e5 + 7;
int main() {
  int n, k = 0;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    char s;
    cout << 'a';
    for (int i = 1; i <= k; i++) {
      s = 'a' + i;
      cout << s;
    }
    for (int j = i + 1; j <= n; j++) {
      s = 'a' + k;
      cout << s;
    }
    k++;
    cout << endl;
  }
}
