static void Main(string[] args)
{
BookStore bookStore = new BookStore();
bookStore.Import(json);
Console.WriteLine($"Quantity of 'Ayn Rand - FountainHead' : {bookStore.Quantity("Ayn Rand - FountainHead")}");
Console.WriteLine($"Buy 'J.K Rowling - Goblet Of fire' and 'Isaac Asimov - Foundation' : {bookStore.Buy("J.K Rowling - Goblet Of fire", "Isaac Asimov - Foundation")}");
Console.ReadLine();
}