You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (5R,7aR,11aR)-5-(2-methoxyphenyl)-1-phenyl-5,7,7a,8-tetrahydropyrrolo[2,1-j]quinoxaline-3,6,9-trione by IUPAC nomenclature, provide its molecular formula.
user
C24H20N2O4
assistant