You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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5-[(2R,6R)-2-[[(2R)-2-(hydroxymethyl)pyrrolidin-1-yl]methyl]-6-methylmorpholin-4-yl]quinoline-8-carbonitrile is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H26N4O2
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