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 (4R,4aS,7aS,12bS)-4-(cyclopropylmethyl)-7-methylidene-2,3,5,6,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-4a,9-diol .
user
C21H25NO3
assistant