You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule N-[(2R,4R,4aS,8aR)-2-(3-hydroxy-4-methoxyphenyl)-3,4,4a,5,6,7,8,8a-octahydro-2H-chromen-4-yl]acetamide ?
user
C18H25NO4
assistant