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 8-chloro-5-[2-(3,4-dichlorophenyl)prop-1-enyl]-2-methyl-3,4-dihydro-1H-pyrido[4,3-b]indole into molecular formula.
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C21H19Cl3N2
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