You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3R)-6-fluoro-3-methyl-10-oxa-2,17,18,21-tetrazatetracyclo[13.5.2.04,9.018,22]docosa-1(21),4(9),5,7,15(22),16,19-heptaen-14-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H17FN4O2
assistant