#include <bits/stdc++.h>
using namespace std;
signed main() {
  long long int n;
  cin >> n;
  string str[n + 1];
  string tmp = "";
  for (long long int i = 0; i < n; ++i) tmp += 'a';
  for (long long int i = 0; i < n + 1; ++i) {
    str[i] = tmp;
    for (long long int j = 0; j < i; ++j) ++str[i][j];
  }
  for (long long int i = 0; i <= n; ++i, cout << endl) cout << str[i];
  return 0;
}
