You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule (E)-2-cyano-3-(3,4-difluorophenyl)-N-(1,5-dimethyl-3-oxo-2-phenylpyrazol-4-yl)prop-2-enamide ?
user
C21H16F2N4O2
assistant