You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named (4S,4aS,10bS)-10b-(4-chlorophenyl)sulfonyl-7,10-difluoro-4-(2-nitrosoethyl)-2,4,4a,5-tetrahydro-1H-pyrano[3,4-c]chromene is given. What is its corresponding molecular formula?
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C20H18ClF2NO5S
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