You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name 1-(6-bromo-1H-indole-2-carbonyl)-2,3,3a,4,5,6,7,7a-octahydroindole-2-carboxylic acid into its molecular formula.
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C18H19BrN2O3
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