You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 9,9-dimethyl-2,7-bis[(E)-4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluoronon-1-enyl]xanthene by IUPAC nomenclature, provide its molecular formula.
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C33H20F26O
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