a-a a-b aaa aab aad aao aar aau aav ab- aba abb abd abo abr abu abv ad- ada adb add ado adr adu adv aoa aob aod aoo aor aou aov ar- ara arb ard aro arr aru arv au- aua aub aud auo aur auv av- ava avb avd avo avr avu b-u baa bab bad bao bar bau bav bba bbb bbd bbo bbr bbu bda bdb bdd bdo bdr bdu bdv boa bob bod boo bor bou bov bra brb brd bro brr bru brv bua bub bud buo bur buu bva bvb bvd bvo bvr bvu bvv daa dab dad dao dar dau dav dba dbb dbd dbo dbr dbu dbv dda ddb ddd ddo ddr ddu doa dob dod doo dor dou dov dra drb drd dro drr dru drv dua dub dud duo dur duv dva dvb dvd dvr dvu oaa oab oad oao oar oau oav ob- oba obb obd obo obr obu obv oda odb odd odo odr odu odv oo- ooa oob ood ooo oor oov or- ora orb ord oro orr oru orv ou- oua oud ouo our ov- ova ovb ovd ovo ovv ra- raa rab rad rao rar rau rav rba rbb rbd rbo rbr rbu rda rdb rdd rdo rdr rdu rdv roa rob rod roo ror rou rov rra rrb rrd rrr rru rua rub rud ruo rur ruu ruv rva rvb rvd rvo rvr rvu rvv ua- uaa uab uad uao uar uau uav uba ubb ubo ubr ubu ubv uda udb udd udo udr udu udv uoa uob uod uoo uor ur- ura urb urd uro urr uru uua uur uuu uva uvb uvo uvu uvv v-a vaa vab vad vao var vau vav vba vbd vbo vbr vbv vdb vdd vdo vdr vdu vdv voa vob vod voo vor vou vov vra vrb vrd vrr vru vur vuv vva vvb vvo vvr vvv