This was a great lecture for laying the foundation. I organized the content along with the practice, so I won't forget it and will use it well in the future. However, like the person below, I was charged about 140,000 won, and I contacted the support team and received a refund because I used it for lecture purposes, but... I think I need guidance on this part. Since I can't listen to the lecture all in one or two days, it seems that I will be charged even at a level other than the free tier. Thank you for the great lecture.