You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-7-[(2S,3R,4S,5S,6R)-4,5-dihydroxy-6-(hydroxymethyl)-3-[(3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxyoxan-2-yl]oxy-5-hydroxy-2-(3-hydroxy-4-methoxyphenyl)-2,3-dihydrochromen-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H34O15
assistant