You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule (2S,4S)-N-[1-(5-benzyl-1,2,4-oxadiazol-3-yl)ethyl]-2-methylpiperidine-4-carboxamide into molecular formula.
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C18H24N4O2
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