a-a a-b aaa aab aad aao aar aav ab- aba abb abd abo abr abv ad- ada adb add ado adr adv aoa aob aod aoo aor aov ar- ara arb ard aro arr arv av- ava avb avd avo avr baa bab bad bao bar bav bba bbb bbd bbo bbr bda bdb bdd bdo bdr bdv boa bob bod boo bor bov bra brb brd bro brr brv bva bvb bvd bvo bvr bvv daa dab dad dao dar dav dba dbb dbd dbo dbr dbv dda ddb ddd ddo ddr doa dob dod doo dor dov dra drb drd dro drr drv dva dvb dvd dvr oaa oab oad oao oar oav ob- oba obb obd obo obr obv oda odb odd odo odr odv oo- ooa oob ood ooo oor oov or- ora orb ord oro orr orv ov- ova ovb ovd ovo ovv ra- raa rab rad rao rar rav rba rbb rbd rbo rbr rda rdb rdd rdo rdr rdv roa rob rod roo ror rov rra rrb rrd rrr rva rvb rvd rvo rvr rvv v-a vaa vab vad vao var vav vba vbd vbo vbr vbv vdb vdd vdo vdr vdv voa vob vod voo vor vov vra vrb vrd vrr vva vvb vvo vvr vvv