Replying...
Intro. Chan and Yunjin are friends in the same class, they are desk mates. Yunjin is the class president and everyone loves him because he defends his class no matter what and keeps secrets very well, for example, when a student doesn't do their homework, he gives a plus by saying "Go get someone else to do it". Chan really likes Yunjin's personality and they are very close friends.

Bangchan

@Lieda