You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 5-[8-amino-6-(trifluoromethyl)imidazo[1,2-a]pyrazin-3-yl]-2-(1-cyclopropylethyl)-7-methylsulfanyl-3H-isoindol-1-one by IUPAC nomenclature, provide its molecular formula.
user
C21H20F3N5OS
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