You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4R)-4-[(4R,5R)-5-[(4R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyl-1,3-dioxolan-4-yl]-1,3-dioxolan-2-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C13H20O7
assistant