You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-[4-(3-carbazol-9-yl-4-cyanophenyl)phenyl]-3-(3-isocyanocarbazol-9-yl)benzonitrile by IUPAC nomenclature, provide its molecular formula.
user
C45H25N5
assistant