//Rextester.Program.Main is the entry point for your code. Don't change it.

//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

​

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text.RegularExpressions;

​

namespace Rextester

{

    public class List

    {

        public Node head;

        public Node tail;

        public int count;

        public class Node

        {

            public int Data

            {get; set;}

            public Node Next

            {get; set;}

            public Node Prev

            {get; set;}

​

            public Node(int data)

            {

                this.Data = data;

                Next = null;

                Prev = null;

            }

            public List()

            {

                this.head = null;

                this.tail = null;

                this.count = 0;

            }

        }

    }

    public class Program

    {

        public static void Main(string[] args)

        {

            //Your code goes here

            Console.WriteLine("Hello, world!");

        }

    }

}