You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (E)-4-(dimethylamino)-N-[3-methoxy-5-[3-(6-methoxypyridin-3-yl)-1H-pyrrolo[2,3-b]pyridin-5-yl]phenyl]but-2-enamide by IUPAC nomenclature, provide its molecular formula.
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C26H27N5O3
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