You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 6-[1-(2-methoxyphenyl)-6,7,8,9-tetrahydro-5H-imidazo[1,2-a]azepin-1-ium-3-yl]chromen-2-one;bromide by IUPAC nomenclature, provide its molecular formula.
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C24H23BrN2O3
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