You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,3R,4S,5R)-2-[6-amino-8-[(3-methoxyphenyl)methylamino]purin-9-yl]-5-(hydroxymethyl)oxolane-3,4-diol The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H22N6O5
assistant