데뷔와 활동 시기에 따라 1세대, 2세대, 3세대 등으로 나뉠 만큼 그 수가 어마어마하게 는 것이 첫 번째다.
The first is that their physical headcounts are extremely large as much as having to divide them up into 1st, 2nd, and 3rd generations depending on their debut year and activity periods.