#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr ll INF = 1LL << 60;
ll n, p;
string s;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  string ans(n, 'a');
  cout << ans << '\n';
  for (int i = 0; i < n - 1; ++i) {
    for (int j = n - 1; j > i; --j) {
      ++ans[j];
      cout << ans << '\n';
    }
  }
  return 0;
}
