using System;

using System.Collections.Generic;

using System.Text.RegularExpressions;

using System.Linq;

public class Program

{

    public static void Main()

    {

        Console.Write("Enter a number between 1 and 3: ");

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

​

        ProcessInput(input);

    }

    public static void ProcessInput(int input)

    {

        try

        {

            switch (input)

            {

                case 1:

                    Console.WriteLine("You selected option 1.");

                    break;

                case 2:

                    Console.WriteLine("You selected option 2.");

                    break;

                case 3:

                    Console.WriteLine("You selected option 3.");

                    break;

                default:

                    Console.WriteLine("Invalid input.");

                    break;

            }

​

            // Some other logic here...

            int result = CalculateSomething(input);

            Console.WriteLine($"The result is: {result}");

        }

        catch (Exception ex)

        {

            Console.WriteLine("An error occurred: " + ex.Message);

        }

    }

    public static int CalculateSomething(int num)

    {

        // Magic number 5, should be replaced with a meaningful constant or parameter

        return num * 5;

    }

​

​

}