You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 3-[(2,4-dichlorophenyl)methyl]-1-(3-methylphenyl)-5,6,7,8-tetrahydro-4H-pyrazolo[3,4-b]azepine .
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C21H21Cl2N3
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