Inspiration, First of all, thank you for using it, and if there was any inconvenience, please understand! Is there any part that seemed like an advertisement? There is a part that was uploaded to Infraon to see the marketing effect, so you are right. And in the future, elementary, middle, high school, and college courses will be uploaded one by one, and the advanced course will start at that time, so please refer to it and use it well in the future. If you have any questions, please leave them in the community below at any time! Sinktree Community Open Chat Room: https://open.kakao.com/o/gG3iydke