You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[(3S)-3-ethenyl-6,7,10-trimethoxy-3,4-dihydro-1H-phenanthro[9,10-c]pyridin-2-yl]but-3-en-1-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C26H27NO4
assistant