You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
10-(2-methoxyethyl)-1-methyl-4-(2-oxo-2-piperidin-1-ylethyl)-1,4,10-triazaspiro[5.6]dodecan-9-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H36N4O3
assistant