You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name ethyl 4-(4-chlorophenyl)-6-[(3-methyl-4-oxothieno[2,3-d]pyrimidin-2-yl)sulfanylmethyl]-2-oxo-3,4-dihydro-1H-pyrimidine-5-carboxylate into its molecular formula.
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C21H19ClN4O4S2
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