#include <bits/stdc++.h>
using namespace std;
int main() {
  int N;
  cin >> N;
  string S;
  if (N == 1) {
    cout << "a" << endl;
  }
  if (N == 2) {
    cout << "aa" << endl;
    cout << "ab" << endl;
  }
  if (N == 3) {
    cout << "aaa" << endl;
    cout << "aab" << endl;
    cout << "aba" << endl;
    cout << "abb" << endl;
    cout << "abc" << endl;
  }
  if (N == 4) {
    cout << "aaaa" << endl;
    cout << "aaab" << endl;
    cout << "aabb" << endl;
    cout << "aabc" << endl;
    cout << "abbb" << endl;
    cout << "abbc" << endl;
    cout << "abcb" << endl;
    cout << "abcc" << endl;
    cout << "abcd" << endl;
  }
}
