The lectures of CEO Lee Ho-jun, whom I trust and watch! Judging from the lectures that are free of unnecessary elements and without any obstructions, it seems that he has put in 200,000 hours of effort, not 10,000 hours. I am sensitive to sound, but it is so good and helpful that he explains in detail even the keyboard input that is invisible to beginners without any keyboard typing noise. I sincerely hope that more people will become experts based on this great lecture.^^