You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named benzyl 4-methylsulfonyl-5-oxo-6-propan-2-yl-3,3a,6,6a-tetrahydro-2H-pyrrolo[3,2-b]pyrrole-1-carboxylate by IUPAC nomenclature, provide its molecular formula.
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C18H24N2O5S
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