You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-cyclopropyl-2-[(6R)-3-oxo-2-(2-pyridin-2-ylethyl)-2,8-diazaspiro[5.5]undecan-8-yl]acetamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H30N4O2
assistant