You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[4-(3,9-diazaspiro[5.5]undecan-3-yl)-6-ethylpyrimidin-5-yl]pyridin-2-amine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H28N6
assistant