This problem is about pizza. You have a circular pizza and you want to slice it
with n straight cuts into the maximum number of pieces possible (not necessarily all
of the same size). Let Pn = this maximum number of pieces you can slice a pizza into
with n cuts. Examples are shown below.
P2 = 4 P3 = 7
Your goal: Find a formula for Pn and give a solid argument for why it works