You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 4-[3-[2-(5-chlorothiophen-2-yl)-2-methoxyethyl]-[1,2,4]triazolo[4,3-a]pyridin-7-yl]-N-(2-methylpyrazol-3-yl)pyrimidin-2-amine .
user
C21H19ClN8OS
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