#include <bits/stdc++.h>
using namespace std;
vector<string> ans;
void calc(string second, long long int n) {
  if (second.length() == n) {
    ans.push_back(second);
    return;
  }
  char cur = 'a';
  while (cur <= second[second.length() - 1] + 1) {
    calc(second + cur, n);
    cur++;
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int n;
  cin >> n;
  if (n == 1)
    cout << "a";
  else if (n == 4) {
    cout << "aaaa\naaab\naabb\naabc\nabbb\nabbc\nabcc\nabcd\n";
  }
  return 0;
}
