You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name [1-[2-(7-fluoro-5-oxido-2-oxo-1,5-naphthyridin-5-ium-1-yl)ethyl]piperidin-4-yl] N-tert-butylcarbamate into its molecular formula.
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C20H27FN4O4
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