You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 4-[[(3S)-3-[(5-ethyl-1,3-oxazol-2-yl)methyl-methylamino]pyrrolidin-1-yl]methyl]-1-methylpyridin-2-one into molecular formula.
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C18H26N4O2
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