bbbb bbbs bblb bbls bibb bibi bibl bibs biis bili bill bils bilu birb biri birl birr birs biru bis- bisl biss bisu blir blis blls blss blub blur blus bril bris brls brrr brrs brsb brsr brus bubb bubi bubs bubu buir buis buiu bulb buli bull buls bulu bur- burb buri burl burr burs buru busi buss busu buus ibis ibri ibss ibus iiii iiis iirs iisi iisr iisu ilir ilis ill- illi ills ilus iri- iril iris irlb irri irrs irul irus isbl isil isis isls isri issi issr isss issu isus iuiu iuss lblr lbrs libr libs libu liii liir liis lilb lili lill lils lilu liri lirl lirr lirs liru lisi liss lisu lius llbs llll lrrr ls-r lsbu lssr lubs luis luli lull lulu luri lurs lusi luss rbbb rbbr rbbs rbis rbsl rbss rib- ribs ribu riis rill rilu riri rirs risi riss risu rius rlls rrrr rsbi rsis rssl rubb rubi rubs rubu ruis rull ruri rurs ruru rusi russ rusu s-ib s-ii sbbs sbsi sbus sibi sibs sibu sil- sili sill sils silu siri sirr sirs siru sisi siss sisu siui sius sl-i slib slir slrs slsu slub slur srib sris srub ssbr ssis ssri ssrl ssrs sssb sssi ssss sub- subb subi subl subs suir suis sul- suli sull sulu sur- suri surr surs suru sus- susi suss susu suus ubbi ubii ubir ubis ubli ubls uirr ulli ullr ulul ulus urbi urbs urib uris uriu urls urri ursi urss ursu urur urus usbl usbr usbs usis uslu ussb ussr usss ussu usui usul usus uulu uuri uusi uuuu