bbbb bbbs bbdd bblb bbls bdls bdsd blbt blls blss blst blts blub blud blus blut bsbd bsdl bssd bsts btdt btss bttb btus bubb bubs bubu budb budd budl buds budu bulb buld bull buls bult bulu buss bust busu but- buts butt buus dbls dbss dbtt dbus dddd ddss ddts ddub dlbd dlst dsls dsst dsts dtss dub- dubb dubs dubu dudd duds dudu dull dult dulu dust duts duul duut lbds ldls llbs lldb llds llll llud lsbu lsds lsts ltbl ltds lubs ludd lull lulu luss lust luts sbbs sbds sbsd sbst sbus sdds sdls sdlt sdsl sdss sdsu slds slst slsu slts slub slud slut ssdd sslt sssb ssss sstb sstd sstl ssts stbd stbs stds stld stlt stss sttd stub stud stul stus stut sub- subb subd subl subs sudd suds sul- suld sull sult sulu sus- susd suss sust susu sutu suus tbbs tbst tddb tdls tdss tsbd tsdb tsst tsts ttbb ttss tttt ttul tubb tubs tubu tudu tull tulu tusd tuss tust tutl tuts tutt tutu ubls ubud udds udsd udsl udts ults ultt ulul ulus usbl usbs usdl usds usdt uslu ussb usss usst ussu ustb usts usul usus utsl uttu uulu uuuu