You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 1-[4-(4-chlorophenyl)sulfonylpiperazin-1-yl]-2-(3,4-dihydro-2H-quinolin-1-yl)ethanone into molecular formula.
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C21H24ClN3O3S
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