You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[[5-(2-ethoxyphenyl)-1,3,4-oxadiazol-2-yl]sulfanyl]-N-(2-ethyl-6-methylphenyl)acetamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H23N3O3S
assistant