You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 6-N-benzyl-4-N-[(2,4-dichlorophenyl)methylideneamino]-2-N,2-N-diethyl-1,3,5-triazine-2,4,6-triamine by IUPAC nomenclature, provide its molecular formula.
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C21H23Cl2N7
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