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 ethyl (4R,4aR,7aR,12bS)-9-methoxy-3-methyl-7-oxo-1,2,4,4a,5,6,7a,13-octahydro-4,12-methanobenzofuro[3,2-e]isoquinoline-11-carboxylate is given. What is its corresponding molecular formula?
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C21H25NO5
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