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