You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(1S)-2-[[(4R,4aS,7aR,12bS)-4a-hydroxy-9-methoxy-3,4,12-trimethyl-2,4,5,7a-tetrahydro-1H-[1]benzofuro[3,2-e]isoquinolin-7-yl]oxy]-2-oxo-1-phenylethyl] octadecanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C45H65NO7
assistant