You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 1-[(7Z)-7-(2,3-dichlorophenyl)-5-methyl-1,2,3,4,5,6-hexahydro-1,2,4,6-tetrazocin-3-yl]-4-methylpiperidin-4-amine;ethane by IUPAC nomenclature, provide its molecular formula.
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C21H38Cl2N6
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