using System;

using System.Threading.Tasks;

public class Program

{

    public static int a {get; set;}

    public static void Main()

    {

        Console.WriteLine("Hello World");

        FuncAsync();

        Console.WriteLine("End");

    }

    public static async Task FuncAsync() 

    {

        a = 1;

        await FuncAsync2();

        Console.WriteLine(a);

        await FuncAsync2();

        Console.WriteLine(a);

        await FuncAsync2();

        Console.WriteLine(a);

        //Task.Run((async()=> FuncAsync2()));

        //Console.WriteLine(a);

        //Task.Run(()=> FuncAsync2());

        //Console.WriteLine(a);

        //Task.Run(()=> FuncAsync2());

        //Console.WriteLine(a);

        //Task.WaitAll();

        //Console.WriteLine(a);

    }

    public static async Task FuncAsync2() 

    {

        a = a+1;

    }

}