You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 2-[4-(5-ethyl-1,2,4-oxadiazol-3-yl)-1,3-dioxo-6,7,8,9-tetrahydro-5H-pyrimido[1,6-a]azepin-2-yl]-N-(2-ethylphenyl)acetamide into molecular formula.
user
C23H27N5O4
assistant