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 (1aR,3aS,5R,7aR)-5-methyl-1a,2,3,3a,4,5-hexahydroindeno[1,7a-b]oxirene-7-carboxylate .
user
C12H16O3
assistant