-er a-a a-b aaa aab aad aae aak aan aar aas ab- aba abb abd abe abk abn abr abs ad- ada adb add ade adk adn adr ads aea aeb aed aee aek aen aer aes aka akb akd ake akk akn akr aks an- ana anb and ane ank ann anr ans ar- ara arb ard are ark arn arr ars as- asa asb asd ase ask asn asr ass baa bab bad bae bak ban bar bas bba bbb bbd bbe bbk bbn bbr bbs bda bdb bdd bde bdk bdr bds be- bea beb bed bee bek ben ber bes bka bkb bke bkk bkn bkr bks bna bnb bnd bne bnk bnn bnr bns bra brb brd bre brk brn brr brs bsa bsb bsd bse bsk bsn bsr bss daa dab dad dae dak dan dar das dba dbb dbd dbe dbk dbn dbr dbs dda ddb ddd dde ddk ddn ddr dds de- dea deb ded dee dek den der des dka dkb dke dkk dkr dks dna dnb dnd dne dnk dnn dnr dns dra drb drd dre drk drn drr drs dsa dsb dsd dse dsk dsn dsr dss eaa eab ead eae eak ean ear eas eba ebb ebd ebe ebk ebn ebr ebs ed- eda edb edd ede edk edn edr eds eea eeb eed eee eek een eer ees eka ekb ekd eke ekr eks en- ena enb end ene enk enn enr ens era erb erd ere erk ern err ers es- esa esb esd ese esk esn esr ess ka- kaa kab kad kae kak kan kar kas kba kbb kbd kbe kbk kbn kbr kbs kda kdb kde kdk kdr kds ke- kea keb ked kee kek ken ker kes kkb kke kkk kkn kkr kks kn- kna knd kne knk knn knr kra krd krk krn krr krs ksa ksb ksd kse ksk ksn ksr kss naa nab nad nae nak nan nar nas nba nbb nbd nbe nbk nbn nbr nbs nda ndb ndd nde ndk ndn ndr nds ne- nea neb ned nee nek nen ner nes nka nke nkk nkn nkr nks nna nnb nne nnk nnn nns nra nrb nrd nre nrk nrn nrr nrs nsa nsb nsd nse nsk nsn nsr nss ra- raa rab rad rae rak ran rar ras rba rbb rbd rbe rbk rbn rbr rbs rda rdb rdd rde rdn rdr rds re- rea reb red ree rek ren rer res rkb rke rkk rks rna rnb rnd rnn rnr rns rra rrb rrd rrk rrn rrr rrs rsa rsb rsd rse rsk rsn rsr rss saa sab sad sae sak san sar sas sba sbb sbd sbe sbk sbn sbr sbs sda sdb sdd sde sdk sdn sdr sds se- sea seb sed see sek sen ser ses sk- ska skb skd ske skk skr sks sna snb snd sne snk snn snr sns sr- sra srb srd sre srk srn srr srs ss- ssa ssb ssd sse ssk ssn ssr sss