You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[1-[2-[6-amino-8-(3-fluorophenyl)-9-methylpurin-2-yl]ethynyl]cyclopentyl] hydrogen sulfate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H18FN5O4S
assistant