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 (6S)-9-fluoro-8-methyl-4-oxa-2,11,17,21,22,25-hexazapentacyclo[17.5.2.02,6.07,12.022,26]hexacosa-1(25),9,11,19(26),20,23-hexaene-3,18-dione is given. What is its corresponding molecular formula?
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C20H21FN6O3
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