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

class Program
{
    static void Main()
    {
        var n = int.Parse(ReadLine());
        for (int i = 0; i < n - 1; i++)
        {
            var d = "";
            for (int j = 0; j < 18; j++)
            {
                if ((i & (1 << j)) != 0) d += (char)('a' + j);
            }
            WriteLine("a" + d + "a");
        }
        WriteLine("an");
    }
}