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 methyl 5-oxo-9b-phenyl-2,3-dihydro-[1,3]thiazolo[2,3-a]isoindole-3-carboxylate is given. What is its corresponding molecular formula?
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C18H15NO3S
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