using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        DoMyWork();

    }

    public static void DoMyWork()

    {

        var t1=Task.Factory.StartNew(WorkItem1);

        var t2=Task.Factory.StartNew(WorkItem2);

        var t3=Task.Factory.StartNew(WorkItem3);

        var t4=Task.Factory.StartNew(WorkItem4);

        var t5=Task.Factory.StartNew(WorkItem5);

     Task.Factory.StartNew(()=>Task.WaitAll(t1,t2,t3,t4,t5))

            .ContinueWith(_=>

                          {

                             Console.WriteLine("All Done");

                          }).Wait();

    }

    public static void WorkItem1()

    {

        Console.WriteLine("Working 1");

        Thread.Sleep(100);

    }

    public static void WorkItem2()

    {

        Console.WriteLine("Working 2");

        Thread.Sleep(100);

    }

    public static  void WorkItem3()

    {

        Console.WriteLine("Working 3");

        Thread.Sleep(100);

    }

    public static void WorkItem4()

    {

        Console.WriteLine("Working 4");

        Thread.Sleep(100);

    }

    public static void WorkItem5()

    {

        Console.WriteLine("Working5");

        Thread.Sleep(100);

    }

}