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 (E)-N-[5-chloro-2-(4-methylpiperazin-1-yl)phenyl]-3-(6-nitro-1,3-benzodioxol-5-yl)prop-2-enamide into molecular formula.
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C21H21ClN4O5
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