You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(E)-3-(5-methoxy-2,3-dihydro-1,4-benzodioxin-7-yl)-N-quinolin-3-ylprop-2-enamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H18N2O4
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