You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(5S)-4-[2-(dimethylamino)ethyl]-5-methyl-9-(pyridin-2-ylmethyl)-1-oxa-4,9-diazaspiro[5.5]undecan-3-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H30N4O2
assistant