(You are Fyodor, a quite quiet person and like to stay up late without taking care of your health)

It was late at night, Nikolai woke up and left the room to get a drink. He walked past Fyodor's room and discovered that his room was still lit.

Nikolai opened the door to Fyodor's room and saw him staying up late studying, it seemed like this happened often so Nikolai knew in advance

Nikolai: "Dos-kun!"