bbbb bbbs bibb bibi bibs biis biku birb biri birk birr birs biru bis- bisk biss bisu brik bris brkb brrr brrs brsb brsr brus bubb bubi bubs bubu buik buir buis buiu buki bukk buku bur- burb buri burk burr burs buru busi busk buss busu buus ibis ibri ibss ibus iiii iiis iirs iisi iisr iisu ikki ikri iksu iri- iris irki irks irri irrs irus isis isku isri issi issr isss issu isus iuiu iuss kbbb kbbi kbbk kbbr kbbs kbbu kbib kbik kbis kbiu kbkb kbkk kbkr kbrb kbri kbrk kbru kbsb kbsi kbsk kbsr kbss kbsu kbub kbuk kbur kbus kbuu kibb kibi kibr kibs kibu kiii kiik kiis kiiu kiki kikk kikr kiku kirb kiri kirk kirr kirs kiru kisi kisk kisr kiss kisu kiur kiuu kkbb kkbi kkbr kkbs kkik kkkk kkrb kkrk kkrr kkrs kksi kksr kkss kksu kkus kkuu krbb krbi krbk krbr krib krik kris krki krkk krkr krks krku krrb krri krrk krrr krrs krsk krsr krss krsu krui kruk krur ksbi ksbr ksbs ksib ksii ksik ksir ksis kskb kskk kskr ksks ksku ksrb ksrr ksrs kssi kssr ksss kssu ksub ksui ksuu kubb kubr kubs kubu kuik kuki kukk kuks kuku kurb kuri kurk kurr kurs kuru kusb kusu kuub kuuk kuur kuuu rbbb rbbr rbbs rbis rbss rib- ribs ribu riis riki rikk riku riri rirs risi risk riss risu rius rkss rrrr rsbi rsis rubb rubi rubs rubu ruis ruki rukk ruku ruri rurs ruru rusi rusk russ rusu s-ib s-ii sbbs sbrk sbsi sbus sibi sibs sibu siik siki sikr siks siku siri sirk sirr sirs siru sisi sisk siss sisu siui sius skik skir skis skiu skss skui skur srib sris srub ssbr ssis ssri ssrs sssb sssi ssss sub- subb subi subs suir suis suki suks suku sur- suri surr surs suru sus- susi susk suss susu suus ubbi ubii ubik ubir ubis uirr ukur urbi urbs urib urik uris uriu urri ursi urss ursu uruk urur urus us-k usbr usbs usis ussb ussr usss ussu usui usus uuri uusi uuuu