Thank you for making a great lecture! I enjoyed the lecture. Especially in the polymorphism part, since you handled the inheritance relationship as a box, I could feel why it works this way. Also, in the exceptional part, if there is a method going up from child to parent, a compilation error occurs if the method is not executed. However, in the case of overriding, I could understand why it was designed in the direction of parent to child. It felt like you knew my curiosity in advance, as if you were giving me a 1:1 tutoring, and I guess you made it with that much passion. I will learn well from your consistent passion even though you have a long career.