You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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5-[6-hydroxy-4-[4-(2-methylpyrazol-3-yl)benzoyl]-1,4-diazepan-1-yl]-5-oxopentanenitrile is the IUPAC name of a molecule. Please give its molecular formula.
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C21H25N5O3
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