using System;
using System.Collections.Generic;
using System.Linq;
using static System.Console;
using static System.Math;

class MainClass
{
    static void Main()
    {
        int N = int.Parse(ReadLine());
        var S = new char[N];
        for (int i = 0; i < N; i++)
        {
            S[i] = 'a';
        }
        WriteLine(string.Join("",S));
        search(S, N);
    }
    static void search(char[] S,int N)
    {
        bool frag = false;
        for (int i = N - 1; i >= 1; i--)
        {
            if (S[i] == S[i - 1])
            {
                S[i]++;
                frag = true;
                break;
            }
            
        }
        if (frag)
        {
            WriteLine(string.Join("",S));
            search(S, N);
        }
    }
}
