You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(E)-2-cyano-N-(3,5-dichlorophenyl)-3-[5-(3-nitrophenyl)furan-2-yl]prop-2-enamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H11Cl2N3O4
assistant