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system
Name the molecular formula for the molecule established as 2-[(7R,12bS)-6-oxo-2,3,4,7,8,12b-hexahydro-1H-pyrido[2,1-a][2]benzazepin-7-yl]isoindole-1,3-dione using the IUPAC nomenclature.
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C22H20N2O3
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