using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        List<Holiday> holidayDifference = new List<Holiday>();

​

        List<Holiday> remoteHolidays = new List<Holiday>

        {

            new Holiday { Name = "Xmas" },

            new Holiday { Name = "Hanukkah" },

            new Holiday { Name = "Ramadan" }

        };

​

        List<Holiday> localHolidays = new List<Holiday>

        {

            new Holiday { Name = "Xmas" },

            new Holiday { Name = "Ramadan" }

        };

​

        holidayDifference = remoteHolidays

            .Except(localHolidays)

            .ToList();

​

        holidayDifference.ForEach(x => Console.WriteLine(x.Name));

    }

}

​

class Holiday : IEquatable<Holiday>

{

    public string Name { get; set; }

​

    public bool Equals(Holiday other)

    {

        return Name == other.Name;

    }

​

    // GetHashCode must return true whenever Equals returns true.

    public override int GetHashCode()

    {

        //Get hash code for the Name field if it is not null.

        return Name?.GetHashCode() ?? 0;

    }

}

​