You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-fluoro-8-[(5-iodo-2,3-dihydro-1-benzothiophen-6-yl)methyl]-9-[3-(propan-2-ylamino)propyl]purin-6-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H24FIN6S
assistant