You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named (6R)-3,4-dimethyl-N-(4-methylphenyl)-2-oxo-6-thiophen-2-yl-1,6-dihydropyrimidine-5-carboxamide is given. What is its corresponding molecular formula?
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C18H19N3O2S
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