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system
Provide the molecular formula for the IUPAC named substance 3-[[(4R)-3,5'-dimethyl-2',6-dioxo-1-(7H-purin-6-yl)spiro[5,7-dihydropyrazolo[3,4-b]pyridine-4,3'-indole]-1'-yl]methyl]benzonitrile .
user
C28H21N9O2
assistant