You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name 9-amino-2-(cyclobutadienyl)-6-fluoro-5-(2-methoxypyridin-3-yl)-3H-pyrrolo[3,4-b]quinolin-1-one into its molecular formula.
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C21H15FN4O2
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