-er a-a a-b a-t aaa aab aad aae aar aat aau ab- aba abb abd abe abr abt abu ad- ada adb add ade adr adt adu aea aeb aed aee aer aet aeu ar- ara arb ard are arr art aru at- ata atb atd ate atr att atu au- aua aub aud aue aur aut b-u baa bab bad bae bar bat bau bba bbb bbd bbe bbr bbt bbu bda bdb bdd bde bdr bdt bdu be- bea beb bed bee ber bet beu bra brb brd bre brr brt bru bta btb btd bte btr btt btu bua bub bud bue bur but buu daa dab dad dae dar dat dau dba dbb dbd dbe dbr dbt dbu dda ddb ddd dde ddr ddt ddu de- dea deb ded dee der det deu dra drb drd dre drr drt dru dta dtb dtd dte dtr dtt dtu dua dub dud due dur dut eaa eab ead eae ear eat eau eba ebb ebd ebe ebr ebt ebu ed- eda edb edd ede edr edt edu eea eeb eed eee eer eet era erb erd ere err ert eru eta etb etd ete etr ett etu eu- eua eub eud eue eur eut ra- raa rab rad rae rar rat rau rba rbb rbd rbe rbr rbt rbu rda rdb rdd rde rdr rdt rdu re- rea reb red ree rer ret reu rra rrb rrd rrr rrt rru rta rtb rtd rte rtr rtt rtu rua rub rud rue rur rut ruu taa tab tad tae tar tat tau tba tbb tbd tbe tbr tbt tbu tda tdb tdd tde tdr tdt tdu te- tea teb ted tee ter tet teu tra trb trd tre trr trt tru tta ttb ttd tte ttr ttt ttu tua tub tud tue tur tut tuu ua- uaa uab uad uae uar uat uau uba ubb ube ubr ubt ubu uda udb udd ude udr udt udu uea ueb ued uee uer uet ur- ura urb urd ure urr urt uru uta utb utd ute utr utt utu uua uue uur uut uuu