bbbb bibb bibi birb biri birr birt biru bitt bitu bmir bmmi brim brit brrm brrr brum brut btrt bttb bubb bubi bubu buir buit buiu bum- bumb bur- burb buri burm burr burt buru but- buti butt ibbm ibim ibri ibtb iiii iiit iitm iitr iitt iium imbi imir imit immi immt imri imrr irbm iri- irri irti itim itri itum itur iuiu mbim miii miit mim- mimi miri mirr mirt miru mit- mitb miti mitm mitt mitu miui mmii mmmm mrbb mrbm mrtm mrtt mtrr mttr mubi muir muit mumm mumu muri murr murt muru muti mutt mutu muut rbbb rbbr rib- ribu rimi rimm rimu riri riti ritt ritu rmtu rrrr rrum rtmi rubb rubi rubu ruit rumb rumi rumm rumt ruri ruru ruti rutt rutu tbit tbrb tibi tibu tiit tiiu timi timm timu tirb tiri tirr tiru titi titt titu tium tmbr tmtt tri- trib trim trit trmb trmi trmu trtr trub trut truu ttbb ttim tttt tubb tubr tubu tuim tuit tuiu tumb tumi tumu turb turi turm turr turt turu tuti tutt tutu tuum ubbi ubii ubir ubit uirr umb- umbi umit umri umut urbi urib urim uriu urmi urri urum urur urut utmb utri utti uttu uuri uuuu