You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 4-[[(Z)-2-chloroethylideneamino]-[(4E)-4-[(Z)-prop-1-enyl]hepta-4,6-dien-1-yn-3-yl]amino]benzenesulfonamide by IUPAC nomenclature, provide its molecular formula.
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C18H20ClN3O2S
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