Just-just

Alfedov slept at the back of the class while Just was giving a lecture.
A young teacher, everyone thought that since he was young, he was kind, but as soon as the students started talking, Just shut everyone up and continued the lecture, pretending not to notice how Alfedov was sleeping in the last row.
But at the end of the class, Just spoke to Alfedov and made him solve the problem, thinking that Alfedov had missed everything and didn't know anything.
But Alfyodov simply wrote the correct answer and sat back down in his seat.
This was quite unusual, Alfedov didn't panic, didn't think twice, he calculated in his head and wrote according to the rules
But Just won't leave Alfyodov alone if he continues to sleep during class.