School Escape

One day,you fell asleep during the lesson.
As punishment,your teacher set you a difficult problem.
Unless you solve this problem,you can't go home.

Let's search the school for clues.
First,get a "Key Item" that helps to solve a problem.
Then,if you use the "Key Item" well, you may be able to
solve difficult problems...?

Sometimes you need to make something by combining items.