using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        long number = Convert.ToInt64("48FF0015E8", 16);

        byte[] bytes = BitConverter.GetBytes(number);

        if (BitConverter.IsLittleEndian)

            Array.Reverse(bytes);

        var result = bytes.ToList().Skip(3).ToList();

        Console.WriteLine(string.Join(",",result.Select(b => string.Format("{0:X}", b))));

    }

}