a-a a-b aaa aab aak aar aas aav ab- aba abb abk abr abs abv aka akb akk akr aks akv ar- ara arb ark arr ars arv as- asa asb ask asr ass asv av- ava avb avk avr avs baa bab bak bar bas bav bba bbb bbk bbr bbs bka bkb bkk bkr bks bkv bra brb brk brr brs brv bsa bsb bsk bsr bss bsv bva bvb bvk bvr bvs bvv ka- kaa kab kak kar kas kav kba kbb kbk kbr kbs kkb kkk kkr kks kkv kra krk krr krs krv ksa ksb ksk ksr kss ksv kva kvb kvk kvr kvs kvv ra- raa rab rak rar ras rav rba rbb rbk rbr rbs rkb rkk rks rkv rra rrb rrk rrr rrs rsa rsb rsk rsr rss rsv rva rvb rvr rvs rvv saa sab sak sar sas sav sba sbb sbk sbr sbs sbv sk- ska skb skk skr sks sr- sra srb srk srr srs srv ss- ssa ssb ssk ssr sss ssv sva svb svk svr svs svv v-a vaa vab vak var vas vav vba vbk vbr vbs vbv vka vkb vra vrb vrk vrr vrs vsa vsb vsk vsr vss vsv vva vvb vvr vvs vvv