As I listened, the explanation was well-written and it was so fun that I finished it all in one day. As Mr. Kim Young-han said, it seemed like the content stayed in my heart, not my head. If a college professor had lectured like this, I would have scolded him with a good lecture evaluation.. I thought so and gave him a good lecture review, so I gave him 5 stars. Why doesn't Inflearn have 10 stars?? It was a lecture that I wouldn't regret devoting an entire weekend to. Thank you. : )