-ol b-u bbb bbc bbk bbl bbo bbu bcb bcc bck bcl bco bcu bkb bkc bkk bkl bko blb blc blk bll blo blu bob boc bok bol boo bou bub buc buk bul buo buu c-- cbb cbc cbk cbl cbo cbu ccb ccc cck ccl cco ccu ckb ckc cko cl- clb clc clk cll clo clu co- cob coc cok col coo cou cub cuc cuk cul cuo cuu kbb kbc kbk kbl kbo kbu kcb kcc kck kcl kcu kkb kkc kkk kkl kku kl- klb klc klo klu kob koc kok kol koo kou kub kuc kuk kul kuu lbb lbc lbk lbl lbo lbu lcb lcc lck lcl lco lcu lkb lkl llb llc llk lll llo llu lob loc lok lol loo lou lub luc luk lul luo luu ob- obb obc obk obl obo obu oc- ocb occ ock ocl oco ocu okb okc okk okl oko oku olb olc olk oll olo olu oo- oob ooc ook ool ooo ou- ouc ouk oul ouo ubb ubc ubk ubl ubo ubu ucb ucc uck ucl uco ucu ukb ukc ukk ukl uku ulb ulc ulk ull ulo ulu uob uoc uok uol uoo uuc uuu