using System;

using System.Threading.Tasks;

public class Program

{

    public static async Task Main()

    {

        Console.WriteLine("Main: starting");

        await A();

        Console.WriteLine("Main: after A");

        await B();

        Console.WriteLine("Main: finishing");

    }

    public static async Task A() 

    {

        Console.WriteLine("A: starting");

        await Task.Delay(1000);

        Console.WriteLine("A: finishing");

    }

    public static async Task B() 

    {

        Console.WriteLine("B: starting");

        await Task.Delay(1000);

        Console.WriteLine("B: finishing");

    }

}