You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 4-[3-(3-spiro[1,9a-dihydrofluorene-9,19'-pentacyclo[14.2.1.05,18.06,11.012,17]nonadeca-3,5(18),6(11),7,9,12(17),13-heptaene]-8'-ylphenyl)phenyl]-1,2,8,9-tetrahydrodibenzothiophene by IUPAC nomenclature, provide its molecular formula.
user
C55H42S
assistant