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What is the molecular formula of the molecule identified by 3-[(6R,8aS)-6-[2-(5-cyanopyridin-3-yl)ethynyl]-3,4,6,7,8,8a-hexahydro-1H-pyrrolo[1,2-a]pyrazin-2-yl]pyrazine-2-carbonitrile ?
user
C20H17N7
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