You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-(3-ethoxyspiro[3.3]heptan-1-yl)-N-methyl-2-(3-oxo-4H-1,4-benzothiazin-2-yl)acetamide into its molecular formula.
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C20H26N2O3S
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