-er a-a a-b aaa aab aad aae aak aar aau ab- aba abb abd abe abk abr abu ad- ada adb add ade adk adr adu aea aeb aed aee aek aer aeu aka akb akd ake akk akr aku ar- ara arb ard are ark arr aru au- aua aub aud aue auk aur b-u baa bab bad bae bak bar bau bba bbb bbd bbe bbk bbr bbu bda bdb bdd bde bdk bdr bdu be- bea beb bed bee bek ber beu bka bkb bke bkk bkr bra brb brd bre brk brr bru bua bub bud bue buk bur buu daa dab dad dae dak dar dau dba dbb dbd dbe dbk dbr dbu dda ddb ddd dde ddk ddr ddu de- dea deb ded dee dek der deu dka dkb dke dkk dkr dku dra drb drd dre drk drr dru dua dub dud due duk dur eaa eab ead eae eak ear eau eba ebb ebd ebe ebk ebr ebu ed- eda edb edd ede edk edr edu eea eeb eed eee eek eer eka ekb ekd eke ekr eku era erb erd ere erk err eru eu- eua eub eud eue eur ka- kaa kab kad kae kak kar kau kba kbb kbd kbe kbk kbr kbu kda kdb kde kdk kdr kdu ke- kea keb ked kee kek ker kkb kke kkk kkr kku kra krd krk krr kru kub kud kue kuk kur kuu ra- raa rab rad rae rak rar rau rba rbb rbd rbe rbk rbr rbu rda rdb rdd rde rdr rdu re- rea reb red ree rek rer reu rkb rke rkk rku rra rrb rrd rrk rrr rru rua rub rud rue ruk rur ruu ua- uaa uab uad uae uak uar uau uba ubb ube ubk ubr ubu uda udb udd ude udk udr udu uea ueb ued uee uer uka ukb uke ukk ukr uku ur- ura urb urd ure urk urr uru uua uue uur uuu