You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (4S,4aS,7S,12bS)-3-(cyclobutylmethyl)-2,5,6,7,7a,8a,9,10,11,11a,12a,13-dodecahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-4,4a,7,9-tetrol .
user
C21H33NO5
assistant