Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
그래프에서 분할선은 데이터의 경계를 나타냅니다.geuraepeseo bunhalsun-eun deiteoui gyeonggye-reul natanabnida.In the graph, the partition line indicates the boundary of the data.