You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance N-(6,6a,7,8,9,10-hexahydro-5H-pyrazino[1,2-a][1,8]naphthyridin-4-yl)-2,3-difluorobenzamide .
user
C18H18F2N4O
assistant