You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 6-hydroxy-1-(2-methoxyphenyl)-5-[(Z)-(2-methylindol-3-ylidene)methyl]pyrimidine-2,4-dione by IUPAC nomenclature, provide its molecular formula.
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C21H17N3O4
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