A little mind teaser for you...

This is really lame, but the Morale Supression Chair thinks it is funny (go figure!) so I've decided to post. Also, I'm hoping to get the posts rolling again....

How good are you in problem solving...
-There is a bus with 7 Girls
-Each girl carries 7 bags
-Inside each bag there is 7 cats
-Every cat has 7 kittens
-All cats have 4 legs each

Question: How many legs are in the bus?