You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4-ethylpiperazin-1-yl)-[2-[2-(trifluoromethyl)anilino]pyrimidin-4-yl]methanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H20F3N5O
assistant