a-a a-b aaa aab aad aak aao aar aav ab- aba abb abd abk abo abr abv ad- ada adb add adk ado adr adv aka akb akd akk ako akr akv aoa aob aod aok aoo aor aov ar- ara arb ard ark aro arr arv av- ava avb avd avk avo avr baa bab bad bak bao bar bav bba bbb bbd bbk bbo bbr bda bdb bdd bdk bdo bdr bdv bka bkb bkk bko bkr bkv boa bob bod bok boo bor bov bra brb brd brk bro brr brv bva bvb bvd bvk bvo bvr bvv daa dab dad dak dao dar dav dba dbb dbd dbk dbo dbr dbv dda ddb ddd ddk ddo ddr dka dkb dkk dko dkr doa dob dod dok doo dor dov dra drb drd drk dro drr drv dva dvb dvd dvk dvr ka- kaa kab kad kak kao kar kav kba kbb kbd kbk kbo kbr kda kdb kdk kdo kdr kkb kkk kkr kkv koa kob kod kok koo kor kra krd krk kro krr krv kva kvb kvk kvo kvr kvv oaa oab oad oak oao oar oav ob- oba obb obd obk obo obr obv oda odb odd odo odr odv oka okb okd okk oko okr oo- ooa oob ood ook ooo oor oov or- ora orb ord ork oro orr orv ov- ova ovb ovd ovo ovv ra- raa rab rad rak rao rar rav rba rbb rbd rbk rbo rbr rda rdb rdd rdo rdr rdv rkb rkk rko rkv roa rob rod rok roo ror rov rra rrb rrd rrk rrr rva rvb rvd rvo rvr rvv v-a vaa vab vad vak vao var vav vba vbd vbk vbo vbr vbv vdb vdd vdk vdo vdr vdv vka vkb voa vob vod vok voo vor vov vra vrb vrd vrk vrr vva vvb vvo vvr vvv