You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[3,5-difluoro-4-(1-methylpyrazol-4-yl)phenyl]-3-(5H-imidazo[5,1-a]isoindol-5-ylmethyl)urea is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H18F2N6O
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