You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(3-chlorophenyl)methyl]-3,4,5,7,8,9,10,10a-octahydro-1H-pyrido[1,2-a][1,4]diazepine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C16H23ClN2
assistant