You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(3,4,4a,5,6,7,8,8a-octahydro-1H-isoquinolin-2-yl)-2-(2,4-dimethylphenyl)ethanamine is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H30N2
assistant