Questions about challenge flags

How many per half?

If you get 2 challenges in a half and you use one but win that challenge do you still have 2 challenges left for that half?

Thanks guys.

No. You get 2 per game win or lose. The first is free so if you lose it it does not cost you a timeout....The second one will cost a timeout so you must have a time out in that half inorder to challenge a play