School setting Kdrama recommendations!

I will some recommendations on dramas with school setting, in particular high school setting. I wanted the focus to be on the interaction between teacher and students, something like Jdorama Gokusen and GTO. I had not watched much modern kdramas.
The only kdramas I watched are historical drama like Dong Yi and Jewel in the Palace. Besides these two historical dramas, the only modern dramas I watched is boys before flowers.  I enjoyed boys before flowers for its romance, but wanted to look for something more of interaction between teacher and students rather than romance. I had not watched such genre type in kdrama.
I will like the focus of the drama to be interactions between teacher and students, and preferred it to be in high school setting although I am fine with any school setting, whether it is preschool, junior school, college or university. Thanks for your recommendations.

i have only watched

Study Group you might like that

• Study Group +1
• Crash Course in Romance- +1 (more teacher orientated) 
• Weak Hero Class- Takes place in a school, not really any teacher interactions though. Just the students. No romance.
• Doctors- First bit takes in the school, then it goes the medical route. But the leads were a teacher at the high school, and a student who later work together at the hospital. Yes, there is romance though. 
• Any of the "School" series. Though, these are romance focused..  School 2021, and School 2017, along with, School 2015