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Name the molecular formula for the molecule established as 5-ethyl-17,18-difluoro-20-hydroxypentacyclo[13.2.2.12,6.17,11.09,13]henicosa-1(17),2(21),3,5,7(20),15,18-heptaen-8-one using the IUPAC nomenclature.
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C23H20F2O2
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