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 9-(2,2-dideuterio-1,3-benzodioxol-5-yl)-4-hydroxy-6,7-bis(hydroxymethyl)-3H-benzo[f][2]benzofuran-1-one .
user
C21H16O7
assistant