-er a-a a-b aaa aab aad aae aak aao aar aau ab- aba abb abd abe abk abo abr abu ad- ada adb add ade adk ado adr adu aea aeb aed aee aek aeo aer aeu aka akb akd ake akk ako akr aku aoa aob aod aoe aok aoo aor aou ar- ara arb ard are ark aro arr aru au- aua aub aud aue auk auo aur b-u baa bab bad bae bak bao bar bau bba bbb bbd bbe bbk bbo bbr bbu bda bdb bdd bde bdk bdo bdr bdu be- bea beb bed bee bek beo ber beu bka bkb bke bkk bko bkr boa bob bod boe bok boo bor bou bra brb brd bre brk bro brr bru bua bub bud bue buk buo bur buu daa dab dad dae dak dao dar dau dba dbb dbd dbe dbk dbo dbr dbu dda ddb ddd dde ddk ddo ddr ddu de- dea deb ded dee dek deo der deu dka dkb dke dkk dko dkr dku doa dob dod doe dok doo dor dou dra drb drd dre drk dro drr dru dua dub dud due duk duo dur eaa eab ead eae eak eao ear eau eba ebb ebd ebe ebk ebo ebr ebu ed- eda edb edd ede edk edo edr edu eea eeb eed eee eek eeo eer eka ekb ekd eke eko ekr eku eo- eoa eob eod eoe eok eoo eor eou era erb erd ere erk ero err eru eu- eua eub eud eue eur ka- kaa kab kad kae kak kao kar kau kba kbb kbd kbe kbk kbo kbr kbu kda kdb kde kdk kdo kdr kdu ke- kea keb ked kee kek keo ker kkb kke kkk kkr kku koa kob kod koe kok koo kor kou kra krd krk kro krr kru kub kud kue kuk kur kuu oaa oab oad oae oak oao oar oau ob- oba obb obd obe obk obo obr obu oda odb odd ode odo odr odu oea oeb oed oee oeo oer oka okb okd oke okk oko okr oku oo- ooa oob ood ook ooo oor or- ora orb ord ore ork oro orr oru ou- oua oud oue ouk ouo our ra- raa rab rad rae rak rao rar rau rba rbb rbd rbe rbk rbo rbr rbu rda rdb rdd rde rdo rdr rdu re- rea reb red ree rek reo rer reu rkb rke rkk rko rku roa rob rod roe rok roo ror rou rra rrb rrd rrk rrr rru rua rub rud rue ruk ruo rur ruu ua- uaa uab uad uae uak uao uar uau uba ubb ube ubk ubo ubr ubu uda udb udd ude udk udo udr udu uea ueb ued uee uer uka ukb uke ukk ukr uku uoa uob uod uoe uok uoo uor ur- ura urb urd ure urk uro urr uru uua uue uur uuu