#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9 + 10;
const int mod = 1e9 + 7;
const int maxn = 1e5 + 10;
int n;
int main() {
  cin >> n;
  string s;
  for (int i = 1; i <= n; i++) s.push_back('a');
  cout << s << endl;
  char c = 'a';
  for (int i = 1; i <= n - 1; i++) {
    ++c;
    for (int j = n - 1; j >= i; j--) {
      s[j] = c;
      cout << s << endl;
    }
  }
  return 0;
}
