You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
18-fluoranthen-3-yl-9,21-dithia-18-azaheptacyclo[18.7.0.02,10.03,8.011,19.012,17.022,27]heptacosa-1(20),2(10),3,5,7,11(19),12,14,16,22,24,26-dodecaene is the IUPAC name of a molecule. Please give its molecular formula.
user
C40H21NS2
assistant