using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;

namespace charsequense
{
    class Program
    {
        static void Main(string[] args)
        {
            StringBuilder str = new StringBuilder();
            List<Char> charList = new List<char>();
            charList.Add('\0');
            for (int i = (int)'a'; i <= (int)'z'; i++)
            {
                charList.Add((char)i);
            }

            foreach (var item in charList)
            {
                str.Append(item);
                foreach (var item1 in charList)
                {
                    str.Append(item1);
                    foreach (var item2 in charList)
                    {
                        if (item2 == '\0') continue;
                        str.Append(item2);
                        Console.WriteLine(str);
                        str.Remove(2, 1);
                       // Thread.Sleep(1);
                    }
                    str.Remove(1, 1);
                }
                str.Remove(0, 1);
            }

            Console.ReadLine();
        }
    }
}