-er a-a a-b aaa aab aae aag aan aar aav ab- aba abb abe abg abn abr abv aea aeb aee aeg aen aer aev ag- aga agb age agg agn agr agv an- ana anb ane ang ann anr anv ar- ara arb are arg arn arr arv av- ava avb ave avg avn avr baa bab bae bag ban bar bav bba bbb bbe bbg bbn bbr be- bea beb bee beg ben ber bev bga bgb bge bgg bgn bgr bgv bna bnb bne bng bnn bnr bnv bra brb bre brg brn brr brv bva bvb bve bvg bvn bvr bvv eaa eab eae eag ean ear eav eba ebb ebe ebg ebn ebr ebv eea eeb eee eeg een eer eev ega egb ege egg egn egr en- ena enb ene eng enn enr env era erb ere erg ern err erv eva evb eve evg evn evr evv gaa gab gae gag gan gar gav gba gbe gbg gbn gbr gbv ge- gea geb gee geg gen ger gev gga ggb ggg ggn ggr ggv gna gnb gne gnn gnr gnv gra grb gre grg grn grr grv gva gvb gve gvg gvn gvr naa nab nae nag nan nar nav nba nbb nbe nbg nbn nbr nbv ne- nea neb nee neg nen ner nev nga ngb nge ngg ngn nna nnb nne nng nnn nnv nra nrb nre nrg nrn nrr nrv nva nvb nve nvg nvn nvv ra- raa rab rae rag ran rar rav rba rbb rbe rbg rbn rbr re- rea reb ree reg ren rer rev rga rgb rge rgg rgn rgr rgv rna rnb rng rnn rnr rnv rra rrb rrg rrn rrr rva rvb rve rvg rvn rvr rvv v-a v-e vaa vab vae vag van var vav vba vbg vbr vbv vea veb vee veg ven ver vga vgg vgn vgr vn- vna vng vnr vnv vra vrb vre vrg vrn vrr vva vvb vvg vvr vvv