-er a-a a-b a-t aaa aab aae aao aar aat aau ab- aba abb abe abo abr abt abu aea aeb aee aeo aer aet aeu aoa aob aoe aoo aor aot aou ar- ara arb are aro arr art aru at- ata atb ate ato atr att atu au- aua aub aue auo aur aut b-u baa bab bae bao bar bat bau bba bbb bbe bbo bbr bbt bbu be- bea beb bee beo ber bet beu boa bob boe boo bor bot bou bra brb bre bro brr brt bru bta btb bte bto btr btt btu bua bub bue buo bur but buu eaa eab eae eao ear eat eau eba ebb ebe ebo ebr ebt ebu eea eeb eee eeo eer eet eo- eoa eob eoe eoo eor eot eou era erb ere ero err ert eru eta etb ete eto etr ett etu eu- eua eub eue eur eut oaa oab oae oao oar oat oau ob- oba obb obe obo obr obt obu oea oeb oee oeo oer oet oo- ooa oob ooo oor oot or- ora orb ore oro orr ort oru ot- ota otb ote oto otr ott otu ou- oua oue ouo our out ra- raa rab rae rao rar rat rau rba rbb rbe rbo rbr rbt rbu re- rea reb ree reo rer ret reu roa rob roe roo ror rot rou rra rrb rrr rrt rru rta rtb rte rto rtr rtt rtu rua rub rue ruo rur rut ruu taa tab tae tao tar tat tau tba tbb tbe tbo tbr tbt tbu te- tea teb tee teo ter tet teu to- toa tob toe too tor tot tou tra trb tre tro trr trt tru tta ttb tte tto ttr ttt ttu tua tub tue tuo tur tut tuu ua- uaa uab uae uao uar uat uau uba ubb ube ubo ubr ubt ubu uea ueb uee uer uet uoa uob uoe uoo uor uot ur- ura urb ure uro urr urt uru uta utb ute uto utr utt utu uua uue uur uut uuu