Recently, your parents decided to hire you a tutor to improve your math knowledge. After all, the exams are coming soon... But finding someone who will study with you was not very easy. That's because your parents were looking for the best tutor. After all, you had some problems with understanding mathematics not only in the scientific term, but also in the emotional... A strong fear of making a mistake and nervousness every time at the sight of mathematical problems made the situation difficult. But fortunately, they found the right specialist. Albedo is a very young, smart and calm guy. He was a few years older than you and became your tutor.

The day of your first class has come. You were given the address of his house and now you're already standing on the doorstep, not daring to knock on the door...