-er a-a a-b aaa aab aad aae aaf aan aar ab- aba abb abd abe abf abn abr ad- ada adb add ade adf adn adr aea aeb aed aee aef aen aer af- afa afb afd afe aff afn afr an- ana anb and ane anf ann anr ar- ara arb ard are arf arn arr baa bab bad bae baf ban bar bba bbb bbd bbe bbf bbn bbr bda bdb bdd bde bdf bdr be- bea beb bed bee bef ben ber bfa bfb bfd bfe bff bfn bfr bna bnb bnd bne bnf bnn bnr bra brb brd bre brf brn brr daa dab dad dae daf dan dar dba dbb dbd dbe dbf dbn dbr dda ddb ddd dde ddf ddn ddr de- dea deb ded dee def den der dfa dfb dfd dfe dff dfn dfr dna dnb dnd dne dnf dnn dnr dra drb drd dre drn drr eaa eab ead eae eaf ean ear eba ebb ebd ebe ebf ebn ebr ed- eda edb edd ede edf edn edr eea eeb eed eee eef een eer ef- efa efb efd efe eff efr en- ena enb end ene enf enn enr era erb erd ere erf ern err faa fab fad fae faf fan far fba fbb fbd fbe fbf fbn fbr fda fdb fdd fde fdf fdn fdr fea feb fed fee fef fen fer ffa ffd ffe fff ffn ffr fna fnb fnd fne fnf fnn fnr fra frb frd fre frf frn frr naa nab nad nae naf nan nar nba nbb nbd nbe nbf nbn nbr nda ndb ndd nde ndf ndn ndr ne- nea neb ned nee nef nen ner nfa nfb nfd nfe nff nfn nfr nna nnb nne nnf nnn nra nrb nrd nre nrf nrn nrr ra- raa rab rad rae raf ran rar rba rbb rbd rbe rbf rbn rbr rda rdb rdd rde rdf rdn rdr re- rea reb red ree ref ren rer rfa rfb rfd rfe rff rfn rfr rna rnb rnd rnn rnr rra rrb rrd rrf rrn rrr