You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(5R,6R)-6-methyl-3-[2-oxo-2-(4-pyridin-1-ium-4-ylpiperazin-1-yl)ethyl]-1,3-diazaspiro[4.5]decane-2,4-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H28N5O3+
assistant