You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 9-methoxy-5-methyl-2-[2-(methylamino)butyl]-6H-pyrrolo[3,4-c]carbazole-1,3-dione;hydrochloride into molecular formula.
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C21H24ClN3O3
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