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What is the molecular formula of the compound with this IUPAC name 8-[(2E)-2-[[6-hydroxy-1-(2-methylphenyl)-4-oxo-2-sulfanylidenepyrimidin-5-yl]methylidene]hydrazinyl]-1,3,7-trimethyl-5H-purin-9-ium-2,6-dione ?
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C20H21N8O4S+
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