You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4R)-1-methyl-4-[2-[(3S)-piperidin-3-yl]-7,8-dihydro-5H-pyrido[4,3-d]pyrimidine-6-carbonyl]pyrrolidin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H25N5O2
assistant