You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
tert-butyl 8a-butyl-6-hydroxy-4-(4-methoxyphenyl)-5-oxo-3-phenoxy-2a,3,4,8-tetrahydro-2H-benzo[cd]indole-1-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C33H39NO6
assistant