You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1R,2S,6S,7R)-4-[(Z)-(3-ethoxy-5-iodo-4-methoxyphenyl)methylideneamino]-4-azatricyclo[5.2.2.02,6]undec-8-ene-3,5-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H21IN2O4
assistant