You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by (4R,4aR,7aR,12bS)-3-(cyclopropylmethyl)-7,7-difluoro-9-methoxy-1,2,4,4a,5,6,7a,13-octahydro-4,12-methanobenzofuro[3,2-e]isoquinolin-11-ol ?
user
C21H25F2NO3
assistant