You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named methyl 7-(4-methylphenyl)-2,4-dioxo-4a,5,6,7,8,8a-hexahydro-1H-pyrido[2,3-d]pyrimidine-5-carboxylate by IUPAC nomenclature, provide its molecular formula.
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C16H19N3O4
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