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What is the molecular formula of the molecule identified by N-[3-[(4aR,7aS)-2-amino-6-pyrazin-2-yl-4,4a,5,7-tetrahydropyrrolo[3,4-d][1,3]thiazin-7a-yl]phenyl]pyrazine-2-carboxamide ?
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C21H20N8OS
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