using System;

public class Program

{

    public static void Main()

    {

        errormsg:

        Console.WriteLine("Enter the first Number");

        int a;

        bool val1= int.TryParse(Console.ReadLine(), out a);

        Console.WriteLine("Enter the second Number");

        int b;

        bool val2= int.TryParse(Console.ReadLine(), out b);

        if(val1 || val2)

        {

            Console.WriteLine("Your first Number:{0}",a);

            Console.WriteLine("Your second Number:{0}",b);

        }

        else

        {

            Console.WriteLine("Enter Valid Number");

            goto errormsg;

        }

        calculation:

        Console.WriteLine("Do you want to Add/Sub/Div or Mul:");

        string culu = Console.ReadLine();

        switch (culu)

            {

                case "Add":

                    int c = a + b;

                    Console.WriteLine("Addition Value is:{0}",c);

                    break;

                case "Sub":

                    int d = a - b;

                    Console.WriteLine("Subtraction Value is:{0}",d);

                    break;

                case "Div":

                    int e = a / b;

                    Console.WriteLine("Division Value is:{0}",e);

                    break;

                case "Mul":

                    int f = a * b;

                    Console.WriteLine("Multiple Value is:{0}",f);

                    break;

                default:

                    break;

            }

        Console.WriteLine("Do you want to Continue");

        Console.WriteLine("1 for Yes");

        Console.WriteLine("0 for Exit");

        int g = int.Parse(Console.ReadLine());

        if (g == 1)

            {

                goto calculation;

            }   

        else

        {

            Console.WriteLine("Tank You....");

        }

    }

}