You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-chloro-3-(2-chlorophenyl)-6-fluoro-2-[(1R)-1-(7H-purin-6-ylamino)propyl]quinazolin-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H16Cl2FN7O
assistant