CONCENTRATION OF CREDIT RISK (Tables)

12 Months Ended

Dec. 31, 2020

Revenues

Concentration Risk [Line Items]

Schedules of concentration of customers

	Years ended December 31,
	2018	2019	2020
	RMB	RMB	RMB
Customer A	943,084	1,564,436	2,214,262
Customer B	*	403,287	794,685

*   Less than 10%

Accounts receivable

Concentration Risk [Line Items]

Schedules of concentration of customers

	As of December 31,
	2019	2020
	RMB	RMB
Customer C	*	107,153
Customer D	*	48,172
Customer E	*	45,525
Customer F	9,275	*
Customer G	7,517	*
Customer H	6,073	*

*   Less than 10%