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 (3R,7aS)-N-[1-(2-ethoxyphenyl)ethyl]-7a-methyl-5-oxo-2,3,6,7-tetrahydropyrrolo[2,1-b][1,3]thiazole-3-carboxamide into molecular formula.
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C18H24N2O3S
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