You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6,17-bis(ethenyl)-3,10-dithiatricyclo[10.2.2.25,8]octadeca-1(15),5(18),6,8(17),12(16),13-hexaene The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H20S2
assistant