Breastfeeding moms

Did you bring formula to the hospital just in case?or do they provide some for ur stay? Did u buy any formula just in case breast feeding didn't work? If so how much did u buy and what's the best kind to buy if I don't know what baby will like or be able to eat? I plan on 100% breastfeeding but I know sometimes it just doesn't work out and don't want to be panicked at the last minute .