You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 3-(4-chlorophenyl)sulfanyl-1-[4-(4-methoxypyrimidin-2-yl)piperazin-1-yl]propan-1-one into molecular formula.
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C18H21ClN4O2S
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