You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 4-(8-ethoxy-2-methylimidazo[1,2-a]pyridin-3-yl)-4-oxo-2-thiophen-2-ylbutanoic acid into molecular formula.
user
C18H18N2O4S
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