You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 4-[6'-(4,6-diphenylpyrimidin-2-yl)spiro[fluorene-9,9'-thioxanthene]-3'-yl]naphthalene-1-carbonitrile .
user
C52H31N3S
assistant