You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4R)-1-cyclopentyl-4-[4-(difluoromethoxy)-3-methoxyphenyl]-6-methyl-2,4-dihydropyrazolo[3,4-d][1,3]thiazin-3-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H21F2N3O3S
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