You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Name the molecular formula for the molecule established as (2R,4aS,10aR)-7-(3,4-difluorophenyl)-2-ethenyl-6,8-difluoro-1,2,3,4,4a,9,10,10a-octahydrophenanthrene using the IUPAC nomenclature.
user
C22H20F4
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