using System;
using System.Collections.Generic;
using System.Text;
namespace y
{
    class Program
    {
        static void Main(string[] args)
        {
            var n = int.Parse(Console.ReadLine());
            var d = new Dictionary<string, int>();
            var sb = new StringBuilder();

            d.Add("", 0);
            int seed = 10;
            for (int i = 0; i < n; i++)
            {
                if (i == n - 1)
                {
                    Console.WriteLine("an");
                    break;
                }

                string s = "";
                while (d.ContainsKey(s))
                {
                    sb.Clear();
                    for (int j = 0; j < 18; j++)
                    {
                        var a = new Random(seed++);
                        sb.Append(((char)('a' + a.Next(0, 26))).ToString());
                    }
                    s = "a" + sb.ToString() + "a";
                }

                d.Add(s, 0);
                Console.WriteLine(s);
            }
        }
    }
}