It's hard to believe that this is a free lecture, and I think I would take this lecture even if it asked me to pay. It's the best cost-effective lecture because it humbly explains difficult concepts one by one and teaches many important concepts. Really, maybe once out of 20 times? There are times when code that doesn't appear in the lecture is slightly modified or added (I might have missed it), but I think it's okay because it's at a level where students can find it on their own while listening to the lecture. Anyway, I successfully completed the course, and it was really helpful. Thank you.