You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule (4'S,4'aS)-9',10'-difluoro-4'-methyl-8'-(4-oxidopyrazin-4-ium-2-yl)spiro[1,3-diazinane-5,5'-2,4,4a,6-tetrahydro-1H-[1,4]oxazino[4,3-a]quinoline]-2,4,6-trione into molecular formula.
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C20H17F2N5O5
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