-er a-a a-b aaa aab aad aae aaf aan aao aar ab- aba abb abd abe abf abn abo abr ad- ada adb add ade adf adn ado adr aea aeb aed aee aef aen aeo aer af- afa afb afd afe aff afn afo afr an- ana anb and ane anf ann ano anr aoa aob aod aoe aof aon aoo aor ar- ara arb ard are arf arn aro arr baa bab bad bae baf ban bao bar bba bbb bbd bbe bbf bbn bbo bbr bda bdb bdd bde bdf bdo bdr be- bea beb bed bee bef ben beo ber bfa bfb bfd bfe bff bfn bfo bfr bna bnb bnd bne bnf bnn bno bnr boa bob bod boe bof bon boo bor bra brb brd bre brf brn bro brr daa dab dad dae daf dan dao dar dba dbb dbd dbe dbf dbn dbo dbr dda ddb ddd dde ddf ddn ddo ddr de- dea deb ded dee def den deo der dfa dfb dfd dfe dff dfn dfo dfr dna dnb dnd dne dnf dnn dno dnr doa dob dod doe dof don doo dor dra drb drd dre drn dro drr eaa eab ead eae eaf ean eao ear eba ebb ebd ebe ebf ebn ebo ebr ed- eda edb edd ede edf edn edo edr eea eeb eed eee eef een eeo eer ef- efa efb efd efe eff efo efr en- ena enb end ene enf enn eno enr eo- eoa eob eod eoe eof eon eoo eor era erb erd ere erf ern ero err faa fab fad fae faf fan fao far fba fbb fbd fbe fbf fbn fbo fbr fda fdb fdd fde fdf fdn fdo fdr fea feb fed fee fef fen feo fer ffa ffd ffe fff ffn ffo ffr fna fnb fnd fne fnf fnn fnr foa fob foe fof fon foo for fra frb frd fre frf frn fro frr naa nab nad nae naf nan nao nar nba nbb nbd nbe nbf nbn nbo nbr nda ndb ndd nde ndf ndn ndo ndr ne- nea neb ned nee nef nen neo ner nfa nfb nfd nfe nff nfn nfo nfr nna nnb nne nnf nnn nno no- noa nob nod noe nof non noo nor nra nrb nrd nre nrf nrn nro nrr oaa oab oad oae oaf oan oao oar ob- oba obb obd obe obf obn obo obr oda odb odd ode odf odn odo odr oea oeb oed oee oef oen oeo oer of- ofa ofb ofd ofe off ofn ofo ofr on- ona onb ond one onf onn ono onr oo- ooa oob ood oof oon ooo oor or- ora orb ord ore orf orn oro orr ra- raa rab rad rae raf ran rao rar rba rbb rbd rbe rbf rbn rbo rbr rda rdb rdd rde rdf rdn rdo rdr re- rea reb red ree ref ren reo rer rfa rfb rfd rfe rff rfn rfo rfr rna rnb rnd rnn rno rnr roa rob rod roe rof ron roo ror rra rrb rrd rrf rrn rrr