You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[4-[4-(4-fluorophenoxy)pyrimidin-2-yl]piperazin-1-yl]-[2-(trifluoromethyl)phenyl]methanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H18F4N4O2
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