You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 4-[4-[2-[(1S)-3,4-dihydro-1H-isochromen-1-yl]ethyl]-4-oxidopiperazin-4-ium-1-yl]benzenesulfonamide into its molecular formula.
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C21H27N3O4S
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