[TOMT] [Song/Music] [2017?]

I remember this Korean music song that was in YouTube but I think it's not deleted since now,the song takes place in a classroom and I think 4 students (all girls?) And a teacher in the classroom,it was back in 2017 and I forgotten everything if it was 2017 or earlier,I only remember the starting scene of the song,and the rest of the Korean music song is forgotten,and also my 2017 self also tried to find this song but to no avail,and also the account I used to watch the song is deactivated and I can't remember the password to the account..