a-a a-b aaa aab aan aar aav ab- aba abb abn abr abv an- ana anb ann anr anv ar- ara arb arn arr arv av- ava avb avn avr baa bab ban bar bav bba bbb bbn bbr bna bnb bnn bnr bnv bra brb brn brr brv bva bvb bvn bvr bvv naa nab nan nar nav nba nbb nbn nbr nbv nna nnb nnn nnv nra nrb nrn nrr nrv nva nvb nvn nvv ra- raa rab ran rar rav rba rbb rbn rbr rna rnb rnn rnr rnv rra rrb rrn rrr rva rvb rvn rvr rvv v-a vaa vab van var vav vba vbr vbv vn- vna vnr vnv vra vrb vrn vrr vva vvb vvr vvv