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system
Name the molecular formula for the molecule established as 2-[3-chloro-7-[(4-fluorophenyl)sulfonylmethylamino]-6,7,8,9-tetrahydropyrido[3,4-b]indolizin-10-yl]acetic acid using the IUPAC nomenclature.
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C20H19ClFN3O4S
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