You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(8-propan-2-yl-3,4,6,7,9,9a-hexahydro-1H-pyrazino[1,2-a]pyrazin-2-yl)ethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C12H23N3O
assistant