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 3-[(4aR,7S,8aR)-2-(cyclobutylmethyl)-7-methyl-1,3,4,5,6,7,8,8a-octahydroisoquinolin-4a-yl]phenol ?
user
C21H31NO
assistant