You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1',3',6',8'-tetratert-butyl-14-(4-tert-butylphenyl)-4-(9-pyridin-2-ylcarbazol-2-yl)oxyspiro[1,14-diazatetracyclo[7.6.1.02,7.013,16]hexadeca-2(7),3,5,9(16),10,12-hexaene-8,9'-fluorene] is the IUPAC name of a molecule. Please give its molecular formula.
user
C69H72N4O
assistant