b-u bbb bbk bbm bbo bbu bkb bkk bkm bko bmb bmk bmm bmo bmu bob bok bom boo bou bub buk bum buo buu kbb kbk kbm kbo kbu kkb kkk kkm kku kmb kmk kmm kmo kmu kob kok kom koo kou kub kuk kum kuu m-o mbb mbk mbm mbo mbu mkb mkk mkm mko mku mmb mmk mmm mmo mmu mob mok mom moo mou mub muk mum muu ob- obb obk obm obo obu okb okk oko oku om- omb omm omo omu oo- oob ook oom ooo ou- ouk oum ouo ubb ubk ubo ubu ukb ukk uku um- umb umm umo umu uob uok uom uoo uum uuu