Hello Minsu. I apologize for any inconvenience in using the lecture..! I will try to add information on how to use the lecture. However, if I can help you use it right away, the Notion I shared has links to all the problems and the answer codes in 4 languages. If you click on the lecture video and scroll down, you will see the link right away!! If I had introduced it in the lecture in advance, you would have found it easily, but I apologize again for the content.! Use it well for your studies ~! Fighting!!