You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl (2R,3R,3aR)-2-[(1R)-1-bromoethyl]-3,3a,4,5,6,7-hexahydro-2H-[1,2]oxazolo[2,3-a]pyridine-3-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C11H18BrNO3
assistant