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What is the molecular formula of the molecule identified by 7-[4-(N'-cyanocarbamimidoyl)piperazin-1-yl]-1-(2,4-difluorophenyl)-6-fluoro-4,5-dioxo-8,8a-dihydro-4aH-1,8-naphthyridine-3-carboxylic acid ?
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C21H18F3N7O4
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