You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named (6R,7R,8aR)-N-(2-hydroxyethyl)-6-(2-methylpropyl)-4-oxo-2-(1,3-thiazol-5-ylmethyl)-1,3,6,7,8,8a-hexahydropyrrolo[1,2-a]pyrazine-7-carboxamide is given. What is its corresponding molecular formula?
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C18H28N4O3S
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