a-a a-b aaa aab aad aar aav ab- aba abb abd abr abv ad- ada adb add adr adv ar- ara arb ard arr arv av- ava avb avd avr baa bab bad bar bav bba bbb bbd bbr bda bdb bdd bdr bdv bra brb brd brr brv bva bvb bvd bvr bvv daa dab dad dar dav dba dbb dbd dbr dbv dda ddb ddd ddr dra drb drd drr drv dva dvb dvd dvr ra- raa rab rad rar rav rba rbb rbd rbr rda rdb rdd rdr rdv rra rrb rrd rrr rva rvb rvd rvr rvv v-a vaa vab vad var vav vba vbd vbr vbv vdb vdd vdr vdv vra vrb vrd vrr vva vvb vvr vvv