bbb bbk bbo bbr bbs bby bkb bkk bko bkr bks bkv bob bok boo bor bos bov boy brb brk bro brr brs brv bry bsb bsk bso bsr bss bsv bsy bvb bvk bvo bvr bvs bvv by- byk byo byr bys kbb kbk kbo kbr kbs kkb kkk kkr kks kkv kky kob kok koo kor kos koy krk kro krr krs krv kry ksb ksk kso ksr kss ksv kvb kvk kvo kvr kvs kvv kyo kyr kys ob- obb obk obo obr obs obv oby okb okk oko okr oks oo- oob ook ooo oor oos oov or- orb ork oro orr ors orv ory os- osb osk oso osr oss osv ov- ovb ovo ovs ovv oyo oys rbb rbk rbo rbr rbs rkb rkk rko rks rkv rky rob rok roo ror ros rov roy rrb rrk rrr rrs rsb rsk rso rsr rss rsv rvb rvo rvr rvs rvv rvy ry- ryk ryo ryr rys ryy sbb sbk sbo sbr sbs sbv sby sk- skb skk sko skr sks sky sob sok soo sor sos sov soy sr- srb srk sro srr srs srv sry ss- ssb ssk sso ssr sss ssv svb svk svo svr svs svv svy sy- syb syk syr sys vbk vbo vbr vbs vbv vkb vob vok voo vor vos vov voy vrb vrk vrr vrs vry vsb vsk vso vsr vss vsv vvb vvo vvr vvs vvv ybr ybs yby ykk yob yok yoo yor yos yoy yro yrs ysb ysk yso ysr yss ysy yvo yvr yvy yyb yys yyy