You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[[5-[[(2R)-2-ethylpiperidin-1-yl]methyl]-1,2,4-oxadiazol-3-yl]methyl]-2-phenylpyrazolo[1,5-a]pyrazin-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H26N6O2
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