#include <bits/stdc++.h>
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma comment(linker, "/stack:200000000")
using namespace std;
void io() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
}
long long n, m;
int main() {
  io();
  cin >> n;
  string s;
  for (long long i = 1; i <= n; ++i) s.push_back('a');
  cout << s << '\n';
  for (int i = n - 1; i; --i) {
    for (int j = 0; j < i; ++j) {
      s[n - 1 - j]++;
      cout << s << '\n';
    }
  }
}
