You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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4-[3-(3-bromo-4-fluorophenyl)-1,2,4-oxadiazol-5-yl]-1-[2-(4-methylphenyl)ethyl]pyrrolidin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
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C21H19BrFN3O2
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