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 3-[(3aR,7aS)-1,3,3a,4,5,6,7,7a-octahydroisoindole-2-carbonyl]-2-benzylidene-4-phenylbut-3-enoic acid .
user
C26H27NO3
assistant