You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[7-fluoro-6-(5-fluoro-1,3-dioxoisoindol-2-yl)-3-oxospiro[1,4-benzoxazine-2,1'-cyclopropane]-4-yl]propanoic acid is the IUPAC name of a molecule. Please give its molecular formula.
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C21H14F2N2O6
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