You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-[2-oxo-2-[(1S,5R)-3-pyrimidin-2-yl-3,6-diazabicyclo[3.2.2]nonan-6-yl]ethyl]pyridin-4-one into its molecular formula.
user
C18H21N5O2
assistant