100!

100! Maybe you play it at school, maybe you play it in your spare time at the office, filling dozen of sheets. 
It is one of the most popular games, which you can always carry around with you; because when you start you can't stop; because getting to the end becomes an obsession; because finishing before your friends is a must. 
Now you can play it anytime, anywhere. 

The game is simple, but finishing is very difficult.