Since it's a corporate ID, I was stingy with leaving class reviews, but I couldn't not leave a review for this person's class. The lecture time and quality are incredible. Of course, since it's used as a company, it's free, but the quality is so cheap that I feel like it's cheap even if I pay for it. The more I listen to the lecture, the more I want to dig deeper, and it's really good, as if it scratches an itch!!