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 2-[(2R)-2-(1,3-benzothiazol-2-yl)pyrrolidin-1-yl]-N-(4-ethoxyphenyl)acetamide is given. What is its corresponding molecular formula?
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C21H23N3O2S
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