You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 3-[6-(2-chlorophenyl)-2-(trifluoromethyl)imidazo[2,1-b][1,3,4]thiadiazol-5-yl]-N-(1-pyridin-2-ylethyl)prop-2-enamide by IUPAC nomenclature, provide its molecular formula.
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C21H15ClF3N5OS
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