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 methyl 4-[(1S,2S,8aR)-1,2,5,5-tetramethyl-2,3,6,7,8,8a-hexahydronaphthalen-1-yl]butanoate .
user
C19H32O2
assistant