a-a a-b aaa aab aak aar aav ab- aba abb abk abr abv aka akb akk akr akv ar- ara arb ark arr arv av- ava avb avk avr baa bab bak bar bav bba bbb bbk bbr bka bkb bkk bkr bkv bra brb brk brr brv bva bvb bvk bvr bvv ka- kaa kab kak kar kav kba kbb kbk kbr kkb kkk kkr kkv kra krk krr krv kva kvb kvk kvr kvv ra- raa rab rak rar rav rba rbb rbk rbr rkb rkk rkv rra rrb rrk rrr rva rvb rvr rvv v-a vaa vab vak var vav vba vbk vbr vbv vka vkb vra vrb vrk vrr vva vvb vvr vvv