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
유개념은 모든 사람에게 적용될 수 있는 개념입니다.yugaenyeomeun modeun saramege jeogyeongdoel su itneun gaenyeomimnida.The concept of universality is a concept that can be applied to all people.