| Schedule of property and equipment, net |
| | | | | | | | | As of | | | | | | | December 31, | | As of December 31, | | | 2024 | | 2025 | | 2025 | | | RMB | | RMB | | US$ | Computer and transmission equipment | | 31,286,142 | | 37,106,123 | | 5,306,105 | Furniture and office equipment | | 1,715,512 | | 2,695,289 | | 385,421 | Leasehold improvements | | 27,530,407 | | 33,375,602 | | 4,772,648 | Motor vehicles | | 816,103 | | 816,103 | | 116,701 | Total property and equipment | | 61,348,164 | | 73,993,117 | | 10,580,875 | Accumulated depreciation | | (45,514,674) | | (50,093,561) | | (7,163,284) | Property and equipment, net | | 15,833,490 | | 23,899,556 | | 3,417,591 |
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