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What is the molecular formula of the molecule 4-[3-[(2R,4S,5R)-4-hydroxy-5-(hydroxymethyl)oxolan-2-yl]-10-oxo-8-(4-oxobutyl)-6,8-dihydro-5H-[1,3,5]oxadiazino[3,4-a]purin-6-yl]butanal ?
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C20H27N5O7
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