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system
Provide the molecular formula for the IUPAC named substance 9-(2,4-dimethoxyphenyl)-1-methyl-3-prop-2-enyl-6,7,8,9a,10,10a-hexahydro-4aH-purino[7,8-a]pyrimidine-2,4-dione .
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C20H27N5O4
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