You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[6-[4-(2,2-difluoroethyl)piperazin-1-yl]pyridin-3-yl]-3-methyl-5-[[5-(trifluoromethyl)pyrazin-2-yl]amino]-1,2-thiazole-4-carboxamide by IUPAC nomenclature, provide its molecular formula.
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C21H21F5N8OS
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