#include <bits/stdc++.h>
using namespace std;
void my_dbg() { cout << endl; }
template <typename Arg, typename... Args>
void my_dbg(Arg A, Args... B) {
  cout << ' ' << A;
  my_dbg(B...);
}
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
const int inf = INT_MAX;
const int ninf = INT_MIN;
const int mod = 1e9 + 7;
const int N = 2e5 + 2;
void solve() {
  int n;
  scanf("%d", &n);
  set<string> normal;
  normal.insert(string(n, 'a'));
  for (int pos = (int)(1); pos < (int)(n); pos++) {
    string here = string(pos, 'a') + 'b' + string(n - pos - 1, 'a');
    normal.insert(here);
  }
  for (auto i : normal) cout << i << '\n';
}
int main() {
  int t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
