-er a-a a-b aaa aab aad aae aao aar aau ab- aba abb abd abe abo abr abu ad- ada adb add ade ado adr adu aea aeb aed aee aeo aer aeu aoa aob aod aoe aoo aor aou ar- ara arb ard are aro arr aru au- aua aub aud aue auo aur b-u baa bab bad bae bao bar bau bba bbb bbd bbe bbo bbr bbu bda bdb bdd bde bdo bdr bdu be- bea beb bed bee beo ber beu boa bob bod boe boo bor bou bra brb brd bre bro brr bru bua bub bud bue buo bur buu daa dab dad dae dao dar dau dba dbb dbd dbe dbo dbr dbu dda ddb ddd dde ddo ddr ddu de- dea deb ded dee deo der deu doa dob dod doe doo dor dou dra drb drd dre dro drr dru dua dub dud due duo dur eaa eab ead eae eao ear eau eba ebb ebd ebe ebo ebr ebu ed- eda edb edd ede edo edr edu eea eeb eed eee eeo eer eo- eoa eob eod eoe eoo eor eou era erb erd ere ero err eru eu- eua eub eud eue eur oaa oab oad oae oao oar oau ob- oba obb obd obe obo obr obu oda odb odd ode odo odr odu oea oeb oed oee oeo oer oo- ooa oob ood ooo oor or- ora orb ord ore oro orr oru ou- oua oud oue ouo our ra- raa rab rad rae rao rar rau rba rbb rbd rbe rbo rbr rbu rda rdb rdd rde rdo rdr rdu re- rea reb red ree reo rer reu roa rob rod roe roo ror rou rra rrb rrd rrr rru rua rub rud rue ruo rur ruu ua- uaa uab uad uae uao uar uau uba ubb ube ubo ubr ubu uda udb udd ude udo udr udu uea ueb ued uee uer uoa uob uod uoe uoo uor ur- ura urb urd ure uro urr uru uua uue uur uuu