You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance N-[(2R,3R,4S,5R)-2-(6-amino-8-thiophen-2-ylpurin-9-yl)-4-hydroxy-5-(hydroxymethyl)oxolan-3-yl]benzamide .
user
C21H20N6O4S
assistant