Hello. Younghan, I am currently taking the basic course after the introductory course. I am studying by changing my attitude to learn and explore each lecture. When you explained the lecture content using UML diagrams, I often thought that I had missed a lot of the basics. I am trying to start the basics again, and there are some difficult parts, but I will try hard with the thought that I am learning how to hold a knife to cook. Thank you for the great lecture.