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)-3-azido-5-[6-[(2,5-dimethoxyphenyl)methylamino]purin-9-yl]-4-hydroxy-N-methyloxolane-2-carboxamide .
user
C20H23N9O5
assistant