-er a-a a-b a-t aaa aab aad aae aag aar aat ab- aba abb abd abe abg abr abt ad- ada adb add ade adg adr adt aea aeb aed aee aeg aer aet ag- aga agb agd age agg agr agt ar- ara arb ard are arg arr art at- ata atb atd ate atg atr att baa bab bad bae bag bar bat bba bbb bbd bbe bbg bbr bbt bda bdb bdd bde bdg bdr bdt be- bea beb bed bee beg ber bet bga bgb bgd bge bgg bgr bgt bra brb brd bre brg brr brt bta btb btd bte btg btr btt daa dab dad dae dag dar dat dba dbb dbd dbe dbg dbr dbt dda ddb ddd dde ddg ddr ddt de- dea deb ded dee deg der det dga dgd dge dgg dgr dgt dra drb drd dre drg drr drt dta dtb dtd dte dtg dtr dtt eaa eab ead eae eag ear eat eba ebb ebd ebe ebg ebr ebt ed- eda edb edd ede edg edr edt eea eeb eed eee eeg eer eet ega egb egd ege egg egr egt era erb erd ere erg err ert eta etb etd ete etg etr ett g-d gaa gab gad gae gag gar gat gba gbd gbe gbg gbr gbt gda gdb gdd gde gdr gdt ge- gea geb ged gee geg ger get gga ggb ggd ggg ggr ggt gra grb grd gre grg grr grt gta gtb gtd gte gtg gtr gtt ra- raa rab rad rae rag rar rat rba rbb rbd rbe rbg rbr rbt rda rdb rdd rde rdg rdr rdt re- rea reb red ree reg rer ret rga rgb rgd rge rgg rgr rgt rra rrb rrd rrg rrr rrt rta rtb rtd rte rtg rtr rtt taa tab tad tae tag tar tat tba tbb tbd tbe tbg tbr tbt tda tdb tdd tde tdg tdr tdt te- tea teb ted tee teg ter tet tga tgb tge tgg tgr tgt tra trb trd tre trg trr trt tta ttb ttd tte ttg ttr ttt