You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[(2S,3R,4R,5S,6R)-4,5-dihydroxy-2-[(2S,3S,4S,5S,6R)-4-hydroxy-6-(hydroxymethyl)-5-methoxy-2-[[(2R,3S,4S,5R)-3,4,5,6-tetrahydroxyoxan-2-yl]methoxy]oxan-3-yl]oxy-6-(hydroxymethyl)oxan-3-yl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H37NO16
assistant