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 9-[3-carbazol-9-yl-5-[3-(2,6-dimethylphenyl)-5-(1-phenylbenzimidazol-2-yl)phenyl]phenyl]carbazole ?
user
C57H40N4
assistant