using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("First number:");

        int num1 = Convert. ToInt32(Console.ReadLine());

        Console.WriteLine("Second number:");

        int num2 = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("--------MENU--------");

        Console.WriteLine("1. a + b");

        Console.WriteLine ("2. a - b");

        Console.WriteLine("3. a * b");

        Console.WriteLine("4. a / b");

        Console.WriteLine ("5. None of the above options");

        int option = Convert.ToInt32(Console. ReadLine());

        switch (option)

        {

        case 1 :

        Console.WriteLine(num1+num2);

                break;

            case 2 :

                Console.WriteLine(num1 - num2);

                break;

            case 3 :

                Console.WriteLine(num1 * num2);

                break;

            case 4 :

                Console.WriteLine(num1/ num2);

                break;

                default :

                Console.WriteLine("None of the above options");

                break;

        };

​

    }

}