You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 9-(11,11-dimethylbenzo[a]fluoren-9-yl)-2-N,4-N,9-triphenyl-4-N-(3-phenylphenyl)-2-N-(4-phenylphenyl)fluorene-2,4-diamine .
user
C74H54N2
assistant