You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-(2-ethyl-6-pyrrolidin-1-yl-2,3,4,5-tetrahydropyridin-3-yl)-5-(1H-pyrrol-3-yl)-3a,7a-dihydro-[1,3]thiazolo[4,5-b]pyridine into its molecular formula.
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C21H27N5S
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