-er a-a a-b aaa aab aae aag aao aar aav ab- aba abb abe abg abo abr abv aea aeb aee aeg aeo aer aev ag- aga agb age agg ago agr agv aoa aob aoe aog aoo aor aov ar- ara arb are arg aro arr arv av- ava avb ave avg avo avr baa bab bae bag bao bar bav bba bbb bbe bbg bbo bbr be- bea beb bee beg beo ber bev bga bgb bge bgg bgo bgr bgv boa bob boe bog boo bor bov bra brb bre brg bro brr brv bva bvb bve bvg bvo bvr bvv eaa eab eae eag eao ear eav eba ebb ebe ebg ebo ebr ebv eea eeb eee eeg eeo eer eev ega egb ege egg ego egr eo- eoa eob eoe eog eoo eor era erb ere erg ero err erv eva evb eve evg evo evr evv gaa gab gae gag gao gar gav gba gbe gbg gbo gbr gbv ge- gea geb gee geg geo ger gev gga ggb ggg ggo ggr ggv goa gob goe gog goo gor gov gra grb gre grg gro grr grv gva gvb gve gvg gvo gvr oaa oab oae oag oao oar oav ob- oba obb obe obg obo obr obv oea oeb oee oeg oeo oer oga oge ogg ogo oo- ooa oob oog ooo oor oov or- ora orb ore org oro orr orv ov- ova ovb ove ovo ovv ra- raa rab rae rag rao rar rav rba rbb rbe rbg rbo rbr re- rea reb ree reg reo rer rev rga rgb rge rgg rgo rgr rgv roa rob roe rog roo ror rov rra rrb rrg rrr rva rvb rve rvg rvo rvr rvv v-a v-e vaa vab vae vag vao var vav vba vbg vbo vbr vbv vea veb vee veg veo ver vga vgg vgo vgr voa vob voe vog voo vor vov vra vrb vre vrg vrr vva vvb vvg vvo vvr vvv