Crystal structure of (1R,2S,3R,4S)-1-(6-(4-fluorophenyl)-7H-[1,2,4]triazolo[ 3,4-b][1,3,4]thiadiazin-3-yl)pentane-1,2,3,4,5-pentaol water (2:7), 2C15H17FN4O5S · 7H2O