You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R)-4-methyl-1'-(3-methylbutyl)-6,10-diphenylspiro[1,5,6,8,10,11,12-heptazatricyclo[7.3.0.03,7]dodeca-3(7),4,8,11-tetraene-2,3'-indole]-2'-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C30H28N8O
assistant