#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int N;
  char data[10] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'};
  cin >> N;
  int n[10] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
  while (1) {
    cout << data[0];
    for (int i = 1; i < N; i++) {
      cout << data[n[i] - 1];
    }
    cout << endl;
    int flag = 1;
    for (int i = 0; i < N; i++) {
      if (n[i] != i + 1) flag = 0;
    }
    if (flag == 1) break;
    n[N - 1]++;
    for (int i = N - 1; i > 1; i--) {
      if (n[i] == n[i - 1] + 2) {
        n[i] = 1;
        n[i - 1]++;
      }
    }
  }
}
