Good Catholic Joke

Two priests were going to Hawaii on vacation and decided that they would make this a real vacation by not wearing anything that would identify them as clergy. 
The next morning, they went to the beach each, dressed in their "tourist" garb and were sitting on beach chairs, enjoying a drink, the sunshine and the scenery when a "drop dead gorgeous" blonde in a tiny bikini came walking straight towards them. They couldn't help but stare and when she passed them, smiled and said, "Good morning Father," "Good morning Father," nodding and addressing each of themindividually, then passed on by. 
They were both stunned. How in the world did she recognize them as priests?
The next day they went back to the store, bought even more outrageous outfits, these were so loud, you could hear them before you even saw them and again settled on the beach in their chairs to enjoy the sunshine, etc. 
After a while, the same gorgeous blonde, wearing a string bikini this time, came walking toward them again. (They were glad they had sunglasses, because their eyes were about to pop out of their heads.) 
Again, she approached them and greeted them individually: "Good morning Father," "Good morning Father," and started to walk away.
One of the priests couldn't stand it and said, "Just a minute young lady. Yes, we are priests, and proud of it, but I have to know, how in the world did YOU know?"
"Oh Father, don't you recognize me? I'm sister Angela!"