using System;

public class Program

{

    public static void Main()

    {

        double result = 0;

        Console.WriteLine("Въведете първото число:");

        double num = double.Parse(Console.ReadLine());

        Console.WriteLine("Въведете второто число:");

        double num2 = double.Parse(Console.ReadLine());

        Console.WriteLine("Изберете действие (1-събиране, 2-изваждане, 3-умножение, 4-деление).");

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

        if (action == 1)

        { result = num+num2 ;

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

        else if (action == 2)

        { result = num-num2 ;

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

        else if (action == 3)

        { result = num*num2 ;

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

        else if (action == 4)

        { if (num2!=0)

        { result = num/num2;

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

         else 

         { Console.WriteLine("Error. Cannot be divided by 0.");}}

         else 

         { Console.WriteLine("Error. Unvalid action");

         }

​

​

    }

}