You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-[5-chloro-4-ethoxy-2-(pyridin-2-ylamino)phenyl]-3-(5-methyl-1,2-oxazol-3-yl)urea into its molecular formula.
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C18H18ClN5O3
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