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 7-(4-chlorophenyl)-2-(2-methoxy-2-oxoethyl)sulfanyl-5-methyl-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylate into its molecular formula.
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C18H19ClN4O4S
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