It's so convenient to code right on the web without installation. Since you explain everything one by one with consideration for beginners, it's fun to follow along and learn. Above all, it's good because you can follow along at a speed that you can type, and it's good that you explain every mistake that beginners often make. I wondered why it didn't work, but it turns out it was my typo. Isn't there more than five stars? Oh, I really like this kind of lecture. This lecture shows the instructor's teaching skills. I'll listen to the pre-class and buy the book right away. I hope the remaining lectures come up soon. Thank you for the great lecture.