-er eee eef eek een eeo eep eer ees ef- efe eff efo efp efr efs eke ekf eko ekp ekr eks en- ene enf enk enn eno enp enr ens eo- eoe eof eok eon eoo eop eor eos ep- epe epf epn epo epp epr eps ere erf erk ern ero erp err ers es- ese esf esk esn eso esp esr ess fee fef fek fen feo fep fer fes ffe fff ffk ffn ffo ffp ffr ffs fkf fkk fkp fne fnf fnk fnn fnp fnr fns foe fof fok fon foo fop for fos fpe fpk fpn fpo fpp fpr fps fre frf frk frn fro frp frr frs fse fsf fsk fsn fso fsp fsr fss ke- kee kef kek ken keo kep ker kes kff kfo kfs kke kkk kkn kkp kkr kks kn- kne knf knk knn kno knp knr koe kof kok kon koo kop kor kos kpe kpf kpk kpn kpo kpp kpr kps krf krk krn kro krp krr krs kse ksf ksk ksn kso ksp ksr kss ne- nee nef nek nen neo nep ner nes nfe nff nfk nfn nfo nfp nfr nfs nke nkf nkk nkn nko nkp nkr nks nne nnf nnk nnn nno nnp nns no- noe nof nok non noo nop nor nos npe npf npn npo npp npr nps nre nrf nrk nrn nro nrp nrr nrs nse nsf nsk nsn nso nsp nsr nss oee oef oen oeo oep oer oes of- ofe off ofn ofo ofp ofr ofs oke okk oko okp okr oks on- one onf onk onn ono onp onr ons oo- oof ook oon ooo oop oor oos op- ope opf opk opn opo opp opr ops or- ore orf ork orn oro orp orr ors os- ose osf osk osn oso osp osr oss p-p pee pef pek pen peo pep per pes pfe pff pfk pfn pfo pfp pfr pfs pke pkf pkn pko pkp pkr pks pn- pne pnf pnk pnn pno pnp pnr pns poe pof pok pon poo pop por pos ppe ppf ppk ppn ppo ppp ppr pps pre prf prk prn pro prp prr prs ps- pse psf psk psn pso psp psr pss re- ree ref rek ren reo rep rer res rfe rff rfk rfn rfo rfp rfr rfs rke rkf rkk rko rkp rks rnn rno rnp rnr rns roe rof rok ron roo rop ror ros rpe rpf rpk rpn rpo rpp rpr rps rrf rrk rrn rrp rrr rrs rse rsf rsk rsn rso rsp rsr rss se- see sef sek sen seo sep ser ses sfe sff sfk sfn sfo sfp sfr sfs sk- ske skf skk sko skp skr sks sne snf snk snn sno snp snr sns soe sof sok son soo sop sor sos spe spf spk spn spo spp spr sps sr- sre srf srk srn sro srp srr srs ss- sse ssf ssk ssn sso ssp ssr sss