using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        Console.WriteLine("Enter a value");

        String number = Console.ReadLine();

        int res = int.Parse(number);

        Console.WriteLine("Enter another number");

        String num = Console.ReadLine();

        int res1 = int.Parse(num);

        Console.WriteLine("Choose an operation (1, -, *, /):");

        string operation = Console.ReadLine();

        int result = 0;

        switch (operation)

        {

            case "1":

                result = res + res1;

                break;

            case "-":

                result = res - res1;

                break;  

        }

        Console.WriteLine("Result:" + result);

    }

}