You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule 6-(4-hydroxy-3,5-dimethylphenyl)-8-methyl-2-(4-nitrophenyl)-3a,4,6,11,11a,11b-hexahydronaphtho[6,7-e]isoindole-1,3,7,10-tetrone ?
user
C31H26N2O7
assistant