You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 2-pyridin-3-yl-1-[(3R)-3-(3-pyridin-4-yl-1,2,4-oxadiazol-5-yl)pyrrolidin-1-yl]ethanone by IUPAC nomenclature, provide its molecular formula.
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C18H17N5O2
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