How many more diapers?

Susan
I know we are not supposed to stock up too much but there are a lot of good coupons out there right now for diapers. 
Currently I have 1 small bag of N and 2 big boxes of 1. I think baby will come out wearing 1s most likely due to size. 
What do you recommend, if any, on additional diapers I can buy beforehand?