You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-(4-fluorophenyl)-17-thia-2,5,7,8-tetrazatetracyclo[8.7.0.03,8.011,16]heptadeca-1(10),2,6,11(16)-tetraen-9-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H15FN4OS
assistant