You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1Z)-2,3,4-trimethoxy-N-[3-(2-phenylethyl)oxadiazol-3-ium-5-yl]benzenecarboximidate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H21N3O5
assistant