You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named (E)-2-cyano-3-[3,5-dichloro-4-(2-methylpropoxy)phenyl]-N-(3-methylphenyl)prop-2-enamide is given. What is its corresponding molecular formula?
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C21H20Cl2N2O2
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