b-u bbb bbk bbo bbu bby bkb bkk bko bkv bob bok boo bou bov boy bub buk buo buu buy bvb bvk bvo bvu bvv by- byk byo byu kbb kbk kbo kbu kkb kkk kku kkv kky kob kok koo kou koy kub kuk kuu kuy kvb kvk kvo kvv kyo kyu ob- obb obk obo obu obv oby okb okk oko oku oo- oob ook ooo oov ou- ouk ouo ov- ovb ovo ovv oyo ubb ubk ubo ubu ubv uby ukb ukk uku uob uok uoo uuu uvb uvo uvu uvv uyo uyu vbk vbo vbv vkb vob vok voo vou vov voy vuk vuv vvb vvo vvv yby ykk yob yok yoo you yoy yuk yuo yuu yuv yuy yvo yvy yyb yyu yyy