You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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4-bromo-3,5-dimethoxy-N-(8-methyl-2,4-dioxo-1,3-diazaspiro[4.5]decan-3-yl)benzamide is the IUPAC name of a molecule. Please give its molecular formula.
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C18H22BrN3O5
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