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Can you give the molecular formula of the molecule 7-[[(3aS,6aR)-6-fluoro-2,3,3a,5,6,6a-hexahydrofuro[3,2-b]furan-3-yl]oxy]-N-(4-bromo-2-chlorophenyl)-6-methoxyquinazolin-4-amine ?
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C21H18BrClFN3O4
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