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 10-thia-13-azatetracyclo[9.9.0.02,7.014,20]icosa-1(11),2(7),3,8,14(20),15,17-heptaen-13-amine ?
user
C18H18N2S
assistant