You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl 2-(6-chloro-4H-3,1-benzothiazin-2-yl)-5-(4-chlorophenyl)-4-methyl-3H-pyrazole-4-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H17Cl2N3O2S
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