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-bromo-6-(7,7-difluoro-10-oxo-3,4,6,8,9,10a-hexahydro-1H-pyrazino[1,2-a]indol-2-yl)-4-fluorophenyl]methyl acetate is given. What is its corresponding molecular formula?
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C20H20BrF3N2O3
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