You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,3R,4S,5R)-2-[6-amino-2-[2-(1H-indol-3-yl)ethoxy]purin-9-yl]-5-ethyloxolane-3,4-diol The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H24N6O4
assistant