You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named tert-butyl 4-[2-[4-chloro-2-(trifluoromethyl)anilino]-2-oxoethyl]piperazine-1-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C18H23ClF3N3O3
assistant