You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl 7-(4-ethylsulfonylphenyl)-1,1-dioxo-2,3-dihydro-1lambda6-benzothiepine-4-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H20O6S2
assistant