Goran Help

using System;
using System.Collections.Generic;
using System.Linq;
using System.Globalization;
using System.Text;
using System.Threading.Tasks;
using System.Numerics;

namespace GettingBetter
{
    class Program
    {
        public static void Main()
        {
            int numberOfBooks = int.Parse(Console.ReadLine());
            Library lib = new Library("books");
            for (int i = 0; i < numberOfBooks; i++)
            {
                var input = Console.ReadLine().Split(' ');
                Book newBook = new Book(input[0], input[1], input[2], input[3], input[4], decimal.Parse(input[5]));
                lib.Books.Add(newBook);
            }
            var sorted = lib.Books
                .OrderByDescending(p => p.Price)
                .ThenByDescending(a => a.Author)
                .ToList();

            var groups = sorted.GroupBy(p => p.Author);

            foreach (var group in groups)
            {
                decimal totalSum = 0;
                foreach (var item in group)
                {
                    totalSum += item.Price;
                }

                Console.WriteLine("{0} -> {1}", group.Key, totalSum);
            }

        }
    }
    class Library
    {
        public string Name { get; set; }
        public List<Book> Books { get; set; }
        public Library(string name)
        {
            Books = new List<Book>();
            Name = name;
        }
    }
    class Book
    {
        public string Title { get; set; }
        public string Author { get; set; }
        public string Publisher { get; set; }
        public string ReleaseDate { get; set; }
        public string ISBN { get; set; }
        public decimal Price { get; set; }
        public Book(string title, string author, string publisher, string releasedate, string isbn, decimal price)
        {
            Title = title;
            Author = author;
            Publisher = publisher;
            ReleaseDate = releasedate;
            ISBN = isbn;
            Price = price;
        }
    }
}