You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(E)-2-cyano-3-(3-methoxy-4-propoxyphenyl)-N-[2-(trifluoromethyl)phenyl]prop-2-enamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H19F3N2O3
assistant