A polysaccharide of unknown structure was isolated, subjected to exhaustive methylation(methylation denotes the addition of a methyl group to a substrate or the substitution of an atom or group by a methyl group), and hydrolyzed. Analysis of the products revealed two methylated sugars: 2,3,6-tri-O-methyl-D-glucose, 2,4-di-O-methyl-D-glucose and 2,3,4,6-tetra-O-methyl-D-glucose. The ratio of these sugars was 20:1:1. determine the structure of the polysaccharide?