You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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3-fluoro-N-[4-[(6-imidazol-1-yl-2-methylpyrimidin-4-yl)amino]phenyl]-4-methoxybenzenesulfonamide The above is the IUPAC name of a molecule. Write its molecular formula.
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C21H19FN6O3S
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