You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-(3,4,4a,5,6,7,8,8a-octahydro-1H-isoquinolin-2-yl)-2-(propan-2-ylamino)butanamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C16H31N3O
assistant