using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        List<string> first = new List<string>()

        {"1", "abcd 2", "xyz 3", " 4 ", "6"};

        List<string> second = new List<string>()

        {"0", "abcd 2", "xyz 3", "5"};

        var mergedList = new List<string>();

        mergedList.AddRange(first);

        mergedList.AddRange(second.Except(first));

        // Output the example

        foreach (var number in second.Except(first))

        {

            Console.WriteLine(number);

        }

    }

}