please answer with explanation

A book has 1000 pages, 80 lines per page, 40 characters per line, and each character requires 2 bytes of storage. We want to store the book's content in a product state of N spin-1/2 particles. There, a logical 0 maps onto a state coefficient of 0, whereas a 1 maps onto a state coefficient of r > 0 (that is the same for all coefficients that differ from 0). At the end, the state is properly normalized. We do dot use the quantum phase degree of freedom, so we are not using all of the potentially available storage capacity of the system. How many spins do you need to store the book