using System;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Starting tasks");

        var task = Sum();

        var task2 = Task.Factory.StartNew(() => { Console.WriteLine("Should output before previous task"); });

        Task.WaitAll(task, task2);

    }

    public static async Task Sum() {

        await Task.Factory.StartNew(async () => {

            await Task.Delay(TimeSpan.FromSeconds(3));

            Console.WriteLine("Task completed");

        });

    }

}