You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4aS,8aR)-1-[2-(methylamino)ethyl]-6-(3-phenoxypropanoyl)-4,4a,5,7,8,8a-hexahydro-3H-1,6-naphthyridin-2-one;hydrochloride is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H30ClN3O3
assistant