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Under IUPAC nomenclature, a molecule named (4R)-N-cyclopentyl-4,8-dimethyl-2-oxo-N-[2-oxo-2-(propan-2-ylamino)ethyl]-3H-pyrido[1,2-a]pyrimidine-4-carboxamide is given. What is its corresponding molecular formula?
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C21H30N4O3
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