Just right! Just exercise the difficulty problem of the head just as quickly as you exercise at the head. I will not make a question that I can not solve if I do not know the definite stone. If you think carefully, we only ask questions that can be solved.

There is also a function that automatically solves, and this will depend on Cho! Any problem is solved within one second. You can also set and solve problems. When I set up a problem which is said to be the most difficult in the world made by a mathematician of Finland, I was able to solve it in less than 1 second.

There is also a hint function.