You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-[(2S,3R,4S,5S,6R)-4,5-dihydroxy-6-(hydroxymethyl)-3-[(2S,3S,4S,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxyoxan-2-yl]-2-(3,4-dihydroxyphenyl)-5-hydroxy-7-methoxychromen-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H32O15
assistant