-er b-p bbb bbe bbk bbn bbo bbp bbr bbs be- beb bee bek ben beo bep ber bes bkb bke bkk bkn bko bkp bkr bks bnb bne bnk bnn bno bnp bnr bns bob boe bok bon boo bop bor bos bpb bpe bpn bpo bpp bpr bps brb bre brk brn bro brp brr brs bsb bse bsk bsn bso bsp bsr bss ebb ebe ebk ebn ebo ebp ebr ebs eeb eee eek een eeo eep eer ees ekb eke eko ekp ekr eks en- enb ene enk enn eno enp enr ens eo- eob eoe eok eon eoo eop eor eos ep- epb epe epn epo epp epr eps erb ere erk ern ero erp err ers es- esb ese esk esn eso esp esr ess kbb kbe kbk kbn kbo kbp kbr kbs ke- keb kee kek ken keo kep ker kes kkb kke kkk kkn kkp kkr kks kn- kne knk knn kno knp knr kob koe kok kon koo kop kor kos kpe kpk kpn kpo kpp kpr kps krk krn kro krp krr krs ksb kse ksk ksn kso ksp ksr kss nbb nbe nbk nbn nbo nbp nbr nbs ne- neb nee nek nen neo nep ner nes nke nkk nkn nko nkp nkr nks nnb nne nnk nnn nno nnp nns no- nob noe nok non noo nop nor nos npb npe npn npo npp npr nps nrb nre nrk nrn nro nrp nrr nrs nsb nse nsk nsn nso nsp nsr nss ob- obb obe obk obn obo obp obr obs oeb oee oen oeo oep oer oes okb oke okk oko okp okr oks on- onb one onk onn ono onp onr ons oo- oob ook oon ooo oop oor oos op- opb ope opk opn opo opp opr ops or- orb ore ork orn oro orp orr ors os- osb ose osk osn oso osp osr oss p-p pbb pbe pbk pbn pbo pbp pbr pbs peb pee pek pen peo pep per pes pkb pke pkn pko pkp pkr pks pn- pnb pne pnk pnn pno pnp pnr pns pob poe pok pon poo pop por pos ppb ppe ppk ppn ppo ppp ppr pps prb pre prk prn pro prp prr prs ps- psb pse psk psn pso psp psr pss rbb rbe rbk rbn rbo rbp rbr rbs re- reb ree rek ren reo rep rer res rkb rke rkk rko rkp rks rnb rnn rno rnp rnr rns rob roe rok ron roo rop ror ros rpb rpe rpk rpn rpo rpp rpr rps rrb rrk rrn rrp rrr rrs rsb rse rsk rsn rso rsp rsr rss sbb sbe sbk sbn sbo sbp sbr sbs se- seb see sek sen seo sep ser ses sk- skb ske skk sko skp skr sks snb sne snk snn sno snp snr sns sob soe sok son soo sop sor sos spb spe spk spn spo spp spr sps sr- srb sre srk srn sro srp srr srs ss- ssb sse ssk ssn sso ssp ssr sss