You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 9-methoxy-3-methyl-1,2,3,4,4a,7,7a,13-octahydro-4,12-methanobenzofuro[3,2-e]isoquinolin-3-ium-7-ol into its molecular formula.
user
C18H22NO3+
assistant