You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-(3-fluoro-4-methoxyphenyl)-13-methoxy-8-thia-5,10-diazatricyclo[7.4.0.02,7]trideca-1(13),2(7),3,9,11-pentaen-6-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H13FN2O3S
assistant