You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule N-[(3S,7S,8aS)-1,4-dioxo-3-propan-2-yl-2,3,6,7,8,8a-hexahydropyrrolo[1,2-a]pyrazin-7-yl]-4-bromobenzamide into molecular formula.
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C17H20BrN3O3
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