You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by 6-fluoro-7-methoxy-4-[6-[sulfamoyl-(3,3,3-trifluoro-2-hydroxypropyl)amino]-2-azaspiro[3.3]heptan-2-yl]quinazoline ?
user
C18H21F4N5O4S
assistant