a-a a-b aaa aab aak aan aav ab- aba abb abk abn abv aka akb akk akn akv an- ana anb ank ann anv av- ava avb avk avn baa bab bak ban bav bba bbb bbk bbn bka bkb bkk bkn bkv bna bnb bnk bnn bnv bva bvb bvk bvn bvv ka- kaa kab kak kan kav kba kbb kbk kbn kkb kkk kkn kkv kn- kna knk knn kva kvb kvk kvn kvv naa nab nak nan nav nba nbb nbk nbn nbv nka nkk nkn nna nnb nnk nnn nnv nva nvb nvk nvn nvv v-a vaa vab vak van vav vba vbk vbv vka vkb vn- vna vnv vva vvb vvv