THEM: hi, i would like the book and 2 hats, i can give you 1 hat and the 2 balls in exchange  YOU: how about i have the book and one other object of your choice?  THEM: i'm open to that, would you take 2 hats and the 2 balls instead though?  YOU: no, i need the book, or else we cannot make a deal.  THEM: okay you can have the book and 1 ball  YOU: deal.