You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,4aR,10bR)-6-(4,6-dimethoxypyridin-3-yl)-9-ethoxy-8-methoxy-1,2,3,4,4a,10b-hexahydrophenanthridin-2-ol The above is the IUPAC name of a molecule. Write its molecular formula.
user
C23H28N2O5
assistant