using System;
using System.Threading;
class Program
{
    public delegate int MathOperation(int a, int b);
    public static int Add(int a, int b)
    {
        Thread.Sleep(2000); 
        return a + b;
    }
    static void Main(string[] args)
    {
        Console.WriteLine("Main Started");
        MathOperation add = Add;
        Console.WriteLine("\nSynchronous call:");
        int syncResult = add(5, 3);
        Console.WriteLine($"Synchronous result: {syncResult}");
        Console.WriteLine("\nAsync call using BeginInvoke:");
        IAsyncResult asyncResult = add.BeginInvoke(20, 20, null, null);
        Console.WriteLine("Main thread continues to run...");
        int asyncResultValue = add.EndInvoke(asyncResult);
        Console.WriteLine($"Asynchronous result: {asyncResultValue}");
        Console.WriteLine("Main Ended");
    }
}