INTANGIBLE ASSETS, NET - Amortization expense on intangible assets (Details) - CNY (¥)	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
INTANGIBLE ASSETS, NET
Total amortization expense	¥ 557,419	¥ 1,940,307	¥ 1,872,150
Estimated future amortization expense
Estimated amortization expense for the year ending 2023	264,453
Estimated amortization expense for the year ending 2024	264,453
Estimated amortization expense for the year ending 2025	250,275
Estimated amortization expense for the year ending 2026	248,986
Estimated amortization expense for the year ending 2027	248,986
Cost of revenues
INTANGIBLE ASSETS, NET
Total amortization expense	194,340	194,340	194,340
General and administrative expenses
INTANGIBLE ASSETS, NET
Total amortization expense	¥ 363,079	¥ 1,745,967	¥ 1,677,810

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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