using System;

public class Program

{

    public static void Main()

    {

        int num1; 

        int num2;

        int result;

        string answer;

        Console.WriteLine("Hello World");

        Console.WriteLine("please enter your first number");

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

        Console.WriteLine("please enter your second number.");

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

        Console.WriteLine("what type of operation would you like to do?");

        Console.WriteLine("plese enter a for addition, s for subtraction, m for multiplication or d for divisio");

        answer=Console.ReadLine();

        if(answer=="a")

        {

            result=num1+num2;

        }

        else if (answer =="s")

        {

        result=num1-num2;

        }

        else if (answer =="m")

        {

        result=num1*num2;

        }

        else

        {

            result = num1/num2;

        }

        Console.WriteLine("The result is"+ result);

        Console.WriteLine("Thank you for using the calculator");

​

        Console.ReadKey();

    }

}