#include <bits/stdc++.h>
using namespace std;
long long int n;
int main() {
  cin >> n;
  string str = "";
  for (long long int i = 0; i < n; i++) {
    str.push_back('a');
  }
  cout << str << endl;
  char sirada = 'b';
  for (long long int i = 0; i < n - 1; i++) {
    for (long long int j = i + 1; j < n; j++) {
      str[j] = sirada;
    }
    cout << str << endl;
    sirada++;
  }
}
