bbbb bbbs bblb bbls blbt blls blss blst blts blub blus blut bnss bsns bsts btss bttb btus bubb bubs bubu bulb bull buls bult bulu bunb bunn buns bunt bunu buss bust busu but- buts butt buus llbs llll lnts lsbu lsts ltbl ltns ltnt lubs lull lulu lunn luns lunt luss lust luts nlls nnls nnnn nnsl nnss nntn nsls nssb nsss nstl nsts nstu nsub ntnu ntsb ntss ntsu nubl nubs null nunn nuns nunt nusl nuss nust nusu nuts nutt nutu sbbs sbst sbtn sbus slln slst slsu slts slub slut snns snub snus ssbn sslt ssns sssb ssss sstb sstl ssts stbs stln stlt stnn stns stss stub stul stun stus stut sub- subb subl subs sul- sull sult sulu sun- sunb sunn suns sunt sunu sus- suss sust susu sutu suus tbbs tbst tnts tnut tsst tsts tsun ttbb ttss tttt ttul tubb tubs tubu tull tulu tunb tunn tuns tunu tuss tust tutl tuts tutt tutu ubls ults ultt ulul ulus unns uns- unst untb unts unus unut usbl usbs uslu usnu ussb usss usst ussu ustb usts usul usun usus utsl uttu uulu uuuu