-er a-a a-b aaa aab aad aae aan aao aar ab- aba abb abd abe abn abo abr ad- ada adb add ade adn ado adr aea aeb aed aee aen aeo aer an- ana anb and ane ann ano anr aoa aob aod aoe aon aoo aor ar- ara arb ard are arn aro arr baa bab bad bae ban bao bar bba bbb bbd bbe bbn bbo bbr bda bdb bdd bde bdo bdr be- bea beb bed bee ben beo ber bna bnb bnd bne bnn bno bnr boa bob bod boe bon boo bor bra brb brd bre brn bro brr daa dab dad dae dan dao dar dba dbb dbd dbe dbn dbo dbr dda ddb ddd dde ddn ddo ddr de- dea deb ded dee den deo der dna dnb dnd dne dnn dno dnr doa dob dod doe don doo dor dra drb drd dre drn dro drr eaa eab ead eae ean eao ear eba ebb ebd ebe ebn ebo ebr ed- eda edb edd ede edn edo edr eea eeb eed eee een eeo eer en- ena enb end ene enn eno enr eo- eoa eob eod eoe eon eoo eor era erb erd ere ern ero err naa nab nad nae nan nao nar nba nbb nbd nbe nbn nbo nbr nda ndb ndd nde ndn ndo ndr ne- nea neb ned nee nen neo ner nna nnb nne nnn nno no- noa nob nod noe non noo nor nra nrb nrd nre nrn nro nrr oaa oab oad oae oan oao oar ob- oba obb obd obe obn obo obr oda odb odd ode odn odo odr oea oeb oed oee oen oeo oer on- ona onb ond one onn ono onr oo- ooa oob ood oon ooo oor or- ora orb ord ore orn oro orr ra- raa rab rad rae ran rao rar rba rbb rbd rbe rbn rbo rbr rda rdb rdd rde rdn rdo rdr re- rea reb red ree ren reo rer rna rnb rnd rnn rno rnr roa rob rod roe ron roo ror rra rrb rrd rrn rrr