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-bromo-2,3-dihydro-1,4-benzodioxin-7-yl)-N-[1-([1,2,4]triazolo[4,3-a]pyridin-3-yl)butyl]acetamide is given. What is its corresponding molecular formula?
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C20H21BrN4O3
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