Which Deck Still Holds More Red

Two 52-card decks. In each deck the number of red cards is unknown and uniform on ${0, 1, \dots, 52}$, independently across decks. You draw cards one at a time from either deck and see their colours. When you stop you pick one deck and are paid the number of red cards still in it.

You have drawn 12 cards from each deck:

deck	red seen	black seen	cards left
A	9	3	40
B	5	7	40

You stop now and take deck A. What is your expected reward?

Answer format: round to 2 decimal places.