#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long n;
  cin >> n;
  string temp = "";
  char x = 'a';
  if (n == 1) {
    cout << x << endl;
    return;
  }
  for (long long i = 0; i < n - 1; i++) {
    temp += x;
  }
  for (long long i = 0; i < n; i++) {
    temp += x;
    cout << temp << endl;
    temp.pop_back();
    x++;
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  { solve(); }
}
