using System;

public class Program

{

    public static int PerformOperation(string command) {

       return command switch

       {

           "SystemTest" => 1,

           "Start" => 2,

           "Stop" => 3,

           "Reset" => 4,

           _ => throw new ArgumentException(nameof(command), "Invalid string value for command"),

       };   

    }

    public static void Main()

    {

        Console.WriteLine("Hello World " + PerformOperation("Start"));

    }

}