#include <bits/stdc++.h>
const int mod = 1e9 + 7;
using namespace std;
char num[10] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'};
char s[15][15];
int main() {
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  int i, j, k;
  for (i = 1; i <= n; i++) {
    int t = 0;
    int op = 1;
    for (j = n; j >= i; j--) {
      s[i][t] = num[0];
      t++;
    }
    for (k = i; k > 1; k--) {
      s[i][t] = num[op];
      t++;
      op++;
    }
  }
  cout << s[1] << endl;
  for (int i = 2; i < n; i++) {
    for (int j = n - i; j >= 1; j--) {
      for (int k = j; k < j + i - 1; k++) {
        int temp = s[i][k];
        s[i][k] = s[i][k + 1];
        s[i][k + 1] = temp;
        cout << s[i] << endl;
      }
    }
  }
  if (n != 1) cout << s[n] << endl;
}
