using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        List<string> myList = new List<string> { "1","2","3","4","5","6","7" };

        string currentStep = "9";

        string nextStep = myList

                .SkipWhile(x => !x.Equals(currentStep))

                .Skip(1)

                .FirstOrDefault();

        Console.WriteLine(nextStep == null);

        Console.WriteLine($"Hello World '{nextStep}' !");

    }

}