#include <bits/stdc++.h>
#include <string>
using namespace std;

int main() {
  
  
  int N, word_length;
  cin >> N;
  
  string word = "abcdefghijklmnopqrstuvwxyz";
  word_length = (word.substr(0,N)).length();
　if(N == 1){
   cout << "a" << endl;
 }else if(N == 2){
   for(int i==0; i < N; i++){
     for(int m = i m < N; m++){
       cout << word[i][m] << endl;
     }
   }
 }
}