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 [(1Z,3E)-1-(7-acetamido-2,3,4-trimethoxy-8,9-dihydro-7H-benzo[7]annulen-5-yl)penta-1,3-dien-3-yl]oxyphosphinous acid .
user
C21H28NO6P
assistant