You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-[4-[6-(2,4-difluorophenoxy)pyrimidin-4-yl]-2-methylpiperazin-1-yl]-2-(4-fluorophenyl)ethanone by IUPAC nomenclature, provide its molecular formula.
user
C23H21F3N4O2
assistant