bbbb bbbs bblb bbls blls blss blub blur blus bnrr bnss brls brns brrr brrs brsb brsr brun brus bsns bubb bubs bubu bulb bull buls bulu bunb bunn buns bunu bur- burb burl burn burr burs buru buss busu buus lblr lbrs llbs llll lrrr ls-r lsbu lssr lubs lull lulu lunn luns lurs luss nlls nlrb nnls nnnn nnsl nnss nrlb nrrl nslr nsls nsnr nsrl nssb nssr nsss nsub nubl nubs null nunn nuns nurl nurn nurr nurs nuru nusl nuss nusu rbbb rbbr rbbs rbsl rbss rlls rnbr rrrr rrun rsnn rsnr rssl rubb rubs rubu rull runn runs rurs ruru russ rusu ruun sbbs sbus slln slrn slrs slsu slub slur snns snrs snub snur snus srnn srub ssbn ssbr ssns ssrl ssrs sssb ssss sub- subb subl subs sul- sull sulu sun- sunb sunn suns sunu sur- surn surr surs suru sus- suss susu suus ubls ullr ulul ulus unns unrs uns- unus urbs urls urns urss ursu urun urur urus usbl usbr usbs uslu usnr usnu ussb ussr usss ussu usul usun usus uulu uuuu