You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(3-methoxyphenyl)-2,3,4,4a,5,6,11,11a-octahydro-1H-pyrido[4,3-b]carbazole is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H24N2O
assistant