Suppose we have 5 boxes with different colours: green, yellow, white, blue, and red boxes. Also suppose that we have 5 books with different colours: green, yellow, white, blue, and red books. We want to put all these books in the boxes, so that no two books end up in the same box, and no book ends up in a box with the same colour. How many ways are there to do this? (Justify your answer. Just writing down the number will not be enough)