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 (3R,4S)-4-(2,5-dimethoxyphenyl)-2-oxo-1-pentyl-3,4-dihydropyrimido[1,2-a]benzimidazole-3-carboxylate is given. What is its corresponding molecular formula?
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C26H31N3O5
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