using System;
using System.Threading;
using System.Threading.Tasks;

public class Test
{
	public static void Main()
	{
		A().Wait();
	}
	
	static async Task A() {
		await B();
		Console.WriteLine(Thread.CurrentThread.ManagedThreadId);
	}
	
	static async Task B() {
		await C();
		Console.WriteLine(Thread.CurrentThread.ManagedThreadId);
	}
	
	static async Task C() {
		await Task.Yield();
		Console.WriteLine(Thread.CurrentThread.ManagedThreadId);
	}
}