You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (2S,3S,4R,5R,6S)-2-[[(1R,3aR,4R,5R,7aS)-1-hydroxy-1-(hydroxymethyl)-7a-methyl-5-propan-2-yl-3,3a,4,5,6,7-hexahydro-2H-inden-4-yl]methoxy]-6-(hydroxymethyl)oxane-3,4,5-triol by IUPAC nomenclature, provide its molecular formula.
user
C21H38O8
assistant