You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[[3-(4-ethoxyphenyl)-1,2,4-oxadiazol-5-yl]methyl]-3-(3-methoxypropyl)-4aH-quinazolin-1-ium-2,4-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H25N4O5+
assistant