using System;

using System.Collections.Generic;

using System.Text;

public class Program

{

    public static void Main()

    {

        Book b = new Book("War and Peace", "Leo Tolstoy", "Penguin");

        Book a = new Book("Crime and punishment", "Fjodor Dostojevski", "Penguin");

        Library library = new Library();

        library.addBook(a);

        library.addBook(b);

        Console.WriteLine(library.ToString());

        Person p = new Person("Thomas", "Fontaine");

        p.lendBook(b, library);

        Console.WriteLine(library.ToString());

    }

}

public class Book

{

    private string title;

    private string author;

    private string publisher;

    public Book(string title, string author, string publisher)

    {

        this.title = title;

        this.author = author;

        this.publisher = publisher;

    }

    public override string ToString()

    {

        return "title: " + title + ", " +

            "author: " + author + ", " +

            "publisher: " + publisher;

    }

}

public class Person

{

    private string firstName;

    private string lastName;

    private List<Book> lendBooks;

    public Person(string firstName, string lastName)

    {

        this.firstName = firstName;

        this.lastName = lastName;

        this.lendBooks = new List<Book>();

    }

    public void lendBook(Book b, Library library){

        lendBooks.Add(b);

        library.lendBook(b);

    }

    public void returnBook(Book b, Library library){

        lendBooks.Remove(b);

        library.addBook(b);

    }

    public override string ToString(){

        return "firstName: " + firstName + "\n" + 

            "lastName: " + lastName + "\n" +

            "lendBooks: " + lendBooks.Count;

    }

}

public class Library

{

    private List<Book> books;

    public Library(){

        this.books = new List<Book>();

    }

    public void addBook (Book b){

        books.Add(b);

    }

    public void lendBook (Book b){

        if(books.Contains(b)){

        books.Remove(b);

        }else{

        Console.WriteLine("Book not found.");

        }

    }

    public override string ToString()

    {

        StringBuilder sb = new StringBuilder();

        if(books.Count > 0){

        sb.Append("Books in library: \n");

        foreach(Book b in books){

            sb.Append(b.ToString() + "\n");

            }

        }else{

             sb.Append("No Book Available.");

        }

        return sb.ToString();

    }

}