You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[4-(4-phenylcyclohexa-1,5-dien-1-yl)phenyl]-N-spiro[fluorene-9,9'-thioxanthene]-4-ylspiro[fluorene-9,9'-thioxanthene]-2-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C68H45NS2
assistant