You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 5-[4-[3-[6-(3-methylbutanoyl)pyridin-2-yl]-3-oxopropyl]pyrazol-1-yl]pyridine-3-carbonitrile by IUPAC nomenclature, provide its molecular formula.
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C22H21N5O2
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