#include <bits/stdc++.h>
using namespace std;
int main() {
  string s = "";
  int n;
  cin >> n;
  string a(n, 'a');
  vector<string> arr;
  arr.push_back(a);
  n--;
  while (n--) {
    for (int i = 0; i < a.size(); i++) {
      a[i]++;
    }
    arr.push_back(a);
  }
  for (int i = 0; i < arr.size(); i++) {
    cout << arr[i] << endl;
  }
}
