You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (E)-3-[[5-benzoyl-3-(4-chlorophenyl)-1,3,4-thiadiazol-2-ylidene]amino]-4-ethoxy-4-oxobut-2-enoic acid .
user
C21H16ClN3O5S
assistant