You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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ethyl 3-(bromomethyl)-8-[(2-chloro-4-fluorophenyl)sulfamoyl]-1,4-dioxaspiro[4.5]dec-6-ene-7-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
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C18H20BrClFNO6S
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