a-a a-b a-t aaa aab aar aat aav ab- aba abb abr abt abv ar- ara arb arr art arv at- ata atb atr att atv av- ava avb avr avt baa bab bar bat bav bba bbb bbr bbt bra brb brr brt brv bta btb btr btt btv bva bvb bvr bvt bvv ra- raa rab rar rat rav rba rbb rbr rbt rra rrb rrr rrt rta rtb rtr rtt rtv rva rvb rvr rvt rvv taa tab tar tat tav tba tbb tbr tbt tbv tra trb trr trt trv tta ttb ttr ttt ttv tva tvb tvr tvt v-a vaa vab var vat vav vba vbr vbv vra vrb vrr vrt vta vtb vtr vtt vtv vva vvb vvr vvt vvv