You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(1S,10S,12S)-4-hydroxy-5-methoxy-9-azatetracyclo[7.5.2.01,10.02,7]hexadeca-2,4,6-trien-12-yl] acetate is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H23NO4
assistant