You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-N,1-N-diphenyl-1-N'-(9-phenylcarbazol-2-yl)-1-N'-(4-phenylphenyl)-9,9'-spirobi[fluorene]-1,1'-diamine is the IUPAC name of a molecule. Please give its molecular formula.
user
C67H45N3
assistant