-er a-a a-b aaa aab aae aao aar aau aav ab- aba abb abe abo abr abu abv aea aeb aee aeo aer aeu aev aoa aob aoe aoo aor aou aov ar- ara arb are aro arr aru arv au- aua aub aue auo aur auv av- ava avb ave avo avr avu b-u baa bab bae bao bar bau bav bba bbb bbe bbo bbr bbu be- bea beb bee beo ber beu bev boa bob boe boo bor bou bov bra brb bre bro brr bru brv bua bub bue buo bur buu bva bvb bve bvo bvr bvu bvv eaa eab eae eao ear eau eav eba ebb ebe ebo ebr ebu ebv eea eeb eee eeo eer eev eo- eoa eob eoe eoo eor eou era erb ere ero err eru erv eu- eua eub eue eur euv eva evb eve evo evr evv oaa oab oae oao oar oau oav ob- oba obb obe obo obr obu obv oea oeb oee oeo oer oo- ooa oob ooo oor oov or- ora orb ore oro orr oru orv ou- oua oue ouo our ov- ova ovb ove ovo ovv ra- raa rab rae rao rar rau rav rba rbb rbe rbo rbr rbu re- rea reb ree reo rer reu rev roa rob roe roo ror rou rov rra rrb rrr rru rua rub rue ruo rur ruu ruv rva rvb rve rvo rvr rvu rvv ua- uaa uab uae uao uar uau uav uba ubb ube ubo ubr ubu ubv uea ueb uee uer uoa uob uoe uoo uor ur- ura urb ure uro urr uru uua uue uur uuu uva uvb uve uvo uvu uvv v-a v-e vaa vab vae vao var vau vav vba vbo vbr vbv vea veb vee veo ver veu voa vob voe voo vor vou vov vra vrb vre vrr vru vue vur vuv vva vvb vvo vvr vvv