You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (4R)-1-(4-chlorophenyl)-4-(2,4-dimethoxyphenyl)-3-methyl-4,8-dihydropyrazolo[3,4-e][1,4]thiazepin-7-one into its molecular formula.
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C21H20ClN3O3S
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