| Schedule of interest and investment income, net |
| | | | | | | | | | | For the years ended December 31, | | | 2023 | | 2024 | | 2025 | | | RMB | | RMB | | RMB | | US$ | Unrealized investment (loss)/income of short-term investments | | (202,012,339) | | 125,179,719 | | 72,933,526 | | 10,429,356 | Realized investment income of short-term investments | | 300,705,577 | | 191,828,265 | | 793,211,793 | | 113,427,777 | Unrealized investment income/(loss) of long-term investments | | 645,974,321 | | (131,604,073) | | (6,218,420) | | (889,222) | Realized investment loss of long-term investments | | (659,477,110) | | — | | — | | — | Investment income of structured deposits | | 59,394,774 | | 49,039,769 | | 18,943,295 | | 2,708,855 | Interest income, net | | 110,747,398 | | 145,618,456 | | 111,498,396 | | 15,944,059 | Total | | 255,332,621 | | 380,062,136 | | 990,368,590 | | 141,620,825 |
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| Schedule of gain/(loss) on derivative instruments |
| | | | | | | | | | | For the years ended December 31, | | | 2023 | | 2024 | | 2025 | | | RMB | | RMB | | RMB | | US$ | Unrealized investment (loss)/income of derivative instruments | | (149,741,836) | | 222,975,608 | | 151,074,089 | | 21,603,307 | Realized investment income/(loss) of derivative instruments | | 303,576,774 | | (203,518,248) | | 37,636,493 | | 5,381,947 | Total | | 153,834,938 | | 19,457,360 | | 188,710,582 | | 26,985,254 |
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