You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
carbanide;cyclopenta-1,3-diene;dibenzylidenehafnium;2,7-ditert-butyl-1,9-dihydrofluoren-1-ide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C42H48Hf-4
assistant