You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-ethyl-3-methyl-4-[3-[4-(pyridin-2-ylamino)butyl]-1,2,4-oxadiazol-5-yl]pentanoic acid The above is the IUPAC name of a molecule. Write its molecular formula.
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C19H28N4O3
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