You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4aS,8aR)-2,4,4a,5,6,7,8,8a-octahydro-1H-pyrido[3,4-b]pyrazin-3-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C7H13N3O
assistant