You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(8R,11S)-8-(3-methylthiophen-2-yl)-11-phenyl-8,10,11,12-tetrahydro-7H-benzo[a][4,7]phenanthrolin-9-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C27H22N2OS
assistant