-er a-a a-b aaa aab aae aak aan aap aar aas ab- aba abb abe abk abn abp abr abs aea aeb aee aek aen aep aer aes aka akb ake akk akn akp akr aks an- ana anb ane ank ann anp anr ans ap- apa apb ape apk apn app apr aps ar- ara arb are ark arn arp arr ars as- asa asb ase ask asn asp asr ass b-p baa bab bae bak ban bap bar bas bba bbb bbe bbk bbn bbp bbr bbs be- bea beb bee bek ben bep ber bes bka bkb bke bkk bkn bkp bkr bks bna bnb bne bnk bnn bnp bnr bns bpa bpb bpe bpn bpp bpr bps bra brb bre brk brn brp brr brs bsa bsb bse bsk bsn bsp bsr bss eaa eab eae eak ean eap ear eas eba ebb ebe ebk ebn ebp ebr ebs eea eeb eee eek een eep eer ees eka ekb eke ekp ekr eks en- ena enb ene enk enn enp enr ens ep- epa epb epe epn epp epr eps era erb ere erk ern erp err ers es- esa esb ese esk esn esp esr ess ka- kaa kab kae kak kan kap kar kas kba kbb kbe kbk kbn kbp kbr kbs ke- kea keb kee kek ken kep ker kes kkb kke kkk kkn kkp kkr kks kn- kna kne knk knn knp knr kpa kpe kpk kpn kpp kpr kps kra krk krn krp krr krs ksa ksb kse ksk ksn ksp ksr kss naa nab nae nak nan nap nar nas nba nbb nbe nbk nbn nbp nbr nbs ne- nea neb nee nek nen nep ner nes nka nke nkk nkn nkp nkr nks nna nnb nne nnk nnn nnp nns npa npb npe npn npp npr nps nra nrb nre nrk nrn nrp nrr nrs nsa nsb nse nsk nsn nsp nsr nss p-p paa pab pae pak pan pap par pas pba pbb pbe pbk pbn pbp pbr pbs pea peb pee pek pen pep per pes pka pkb pke pkn pkp pkr pks pn- pna pnb pne pnk pnn pnp pnr pns ppa ppb ppe ppk ppn ppp ppr pps pra prb pre prk prn prp prr prs ps- psa psb pse psk psn psp psr pss ra- raa rab rae rak ran rap rar ras rba rbb rbe rbk rbn rbp rbr rbs re- rea reb ree rek ren rep rer res rkb rke rkk rkp rks rna rnb rnn rnp rnr rns rpa rpb rpe rpk rpn rpp rpr rps rra rrb rrk rrn rrp rrr rrs rsa rsb rse rsk rsn rsp rsr rss saa sab sae sak san sap sar sas sba sbb sbe sbk sbn sbp sbr sbs se- sea seb see sek sen sep ser ses sk- ska skb ske skk skp skr sks sna snb sne snk snn snp snr sns spa spb spe spk spn spp spr sps sr- sra srb sre srk srn srp srr srs ss- ssa ssb sse ssk ssn ssp ssr sss