Snow Leopard and his funny list of videos

Snow leopard recently got a collection of ‘A’ really funny videos. He has a software which helps him make different playlists of C videos out of all the videos. Everytime he uses the software, he gets a new playlist eveytime. He found out the algorithm used by the software for this. - Each video should be played. -Between the two videos, there should be atleast ‘B’ different videos. Help snow l