You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name [(2S)-2-[3-(3-chlorophenyl)-1,2,4-oxadiazol-5-yl]pyrrolidin-1-yl]-(4-methoxyphenyl)methanone into its molecular formula.
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C20H18ClN3O3
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