Statement

Your friend John works at a shop that sells N types of products, numbered from 0 to N-1. Product i has a price of P_i bytedollars, where P_i is a positive integer. The government of Byteland has created a new law for shops. The law states that the average of the prices of all products in a shop should be exactly K, where K is a positive integer. John's boss gave him the task to change the prices of the products so the shop would comply with the new law. \footnotetextPhoto credits: Diego Delso, http://delso.photodelso.photo, License CC-BY-SA He has lots of other stuff to do, so he asked you for help: what is the minimum number of products whose prices should be changed? A product's price can be changed to any positive integer amount of bytedollars.