You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 1-[4-[(7-pyridin-3-yl-5H-pyrrolo[2,3-b]pyrazin-2-yl)oxy]piperidin-1-yl]prop-2-en-1-one by IUPAC nomenclature, provide its molecular formula.
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C19H19N5O2
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