You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 2-(5-chlorothiophen-2-yl)-N-[2-(diethylamino)ethyl]-N-(4-ethyl-1,3-benzothiazol-2-yl)acetamide by IUPAC nomenclature, provide its molecular formula.
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C21H26ClN3OS2
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