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 (2S,3S,4R,5R)-5-[2-(5-chloropyridin-3-yl)-6-(1,3-thiazol-4-ylmethylamino)purin-9-yl]-3,4-dihydroxy-N-methyloxolane-2-carboxamide .
user
C20H19ClN8O4S
assistant