#include <bits/stdc++.h>
using namespace std;
int main(void) {
  long long N;
  cin >> N;
  string s(N, 'a');
  if (N == 1) {
    cout << s << endl;
    return 0;
  }
  long long itr = 0;
  bool back = false;
  while (true) {
    if (back) {
      if (itr == 0) {
        break;
      }
      s[itr]++;
      if (s[itr] >= s[itr - 1] + 2) {
        s[itr] = 'a';
        back = true;
        itr--;
        continue;
      }
      back = false;
      itr++;
    }
    long long itr2 = itr + 1;
    if (itr2 >= N) {
      cout << s << endl;
      s[itr]++;
      if (s[itr] >= s[itr - 1] + 2) {
        s[itr] = 'a';
        back = true;
        itr--;
        continue;
      }
      continue;
    }
    itr++;
  }
}
