#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int n;
  cin >> n;
  string s = "aa";
  if (n == 1)
    cout << "a" << endl;
  else {
    char first = 'b';
    cout << s << endl;
    for (int i = 2; i <= n; i++) {
      s[1] = first;
      cout << s << endl;
      first++;
    }
  }
}
