CCU vs Active Users

I have a game where players connect to a room to get a task, example coloring. But once the task is assigned, players perform the task without any interaction with server i.e. unity handles the rest of things. The game ends when the first person completes his task, and announced winner. So the room has to be intact but players are idle from photon perspective. In such cases, how does photon handle CCU vs active user? Or can I optimally handle such interactions, and save on CCU usage?