You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(2R)-1-(3-cyanoanilino)-1-oxopropan-2-yl] (E)-3-(3,4-dimethoxyphenyl)prop-2-enoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H20N2O5
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