You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1aR,1bS,5aR,6R,6aS)-6-hydroxy-6-(hydroxymethyl)-1b-methyl-1a,2,4,5,5a,6a-hexahydro-1H-cyclopropa[a]inden-3-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C12H18O3
assistant