You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[4-[4-[2-nitro-4-(trifluoromethyl)phenyl]piperazine-1-carbonyl]phenyl]chromen-2-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C27H20F3N3O5
assistant