You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule N-[2-[4-(cyclobutanecarbonyl)piperazin-1-yl]ethyl]-N'-methyl-2-oxa-7-azaspiro[4.4]nonane-7-carboximidamide into molecular formula.
user
C20H35N5O2
assistant