You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1S,3aS,5S,6aS)-1-(hydroxymethyl)-5-(2-methoxyethoxymethoxy)-3,3a,4,5,6,6a-hexahydro-1H-pentalen-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C13H22O5
assistant