You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[4-(5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazin-3-yl)piperidine-1-carbonyl]-1H-quinolin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H22N6O2
assistant