You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 2-(6-chloro-7-methoxy-4-methyl-2-oxochromen-3-yl)-N-[(3S)-1,1-dioxothiolan-3-yl]-N-methylacetamide is given. What is its corresponding molecular formula?
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C18H20ClNO6S
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