You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[2-[2-[4-(difluoromethoxy)phenyl]ethylamino]-2-oxoethyl] (E)-3-[3-(trifluoromethyl)phenyl]prop-2-enoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H18F5NO4
assistant