You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 9-(2-methoxyphenyl)-1,2,3,4,4a,8,9,10,11,11a-decahydrobenzo[b][1,4]benzodiazepin-7-one ?
user
C20H24N2O2
assistant