a-a a-b a-c aaa aab aac aak aao aau aav ab- aba abb abc abk abo abu abv ac- aca acb acc ack aco acu acv aka akb akc akk ako aku akv aoa aob aoc aok aoo aou aov au- aua aub auc auk auo auv av- ava avb avc avk avo avu b-u baa bab bac bak bao bau bav bba bbb bbc bbk bbo bbu bca bcb bcc bck bco bcu bcv bka bkb bkc bkk bko bkv boa bob boc bok boo bou bov bua bub buc buk buo buu bva bvb bvc bvk bvo bvu bvv c-- caa cab cac cak cao cau cav cba cbb cbc cbk cbo cbu cbv cca ccb ccc cck cco ccu ccv cka ckb ckc cko co- coa cob coc cok coo cou cov cua cub cuc cuk cuo cuu cuv cva cvb cvc cvk cvo cvu cvv ka- kaa kab kac kak kao kau kav kba kbb kbc kbk kbo kbu kca kcb kcc kck kcu kkb kkc kkk kku kkv koa kob koc kok koo kou kub kuc kuk kuu kva kvb kvk kvo kvv oaa oab oac oak oao oau oav ob- oba obb obc obk obo obu obv oc- oca ocb occ ock oco ocu ocv oka okb okc okk oko oku oo- ooa oob ooc ook ooo oov ou- oua ouc ouk ouo ov- ova ovb ovc ovo ovv ua- uaa uab uac uak uao uau uav uba ubb ubc ubk ubo ubu ubv uca ucb ucc uck uco ucu ucv uka ukb ukc ukk uku uoa uob uoc uok uoo uua uuc uuu uva uvb uvc uvo uvu uvv v-a vaa vab vac vak vao vau vav vba vbc vbk vbo vbv vca vcc vco vcu vka vkb voa vob voc vok voo vou vov vuk vuv vva vvb vvc vvo vvv