-er eee eef eek eeo eep eer ees ef- efe eff efi efo efp efr efs eie eif eii eik eio eip eir eis eke ekf eki eko ekp ekr eks eo- eoe eof eoi eok eoo eop eor eos ep- epe epf epi epo epp epr eps ere erf eri erk ero erp err ers es- ese esf esi esk eso esp esr ess fee fef fei fek feo fep fer fes ffe fff ffi ffk ffo ffp ffr ffs fie fif fii fik fip fir fis fkf fki fkk fkp foe fof foi fok foo fop for fos fpe fpi fpk fpo fpp fpr fps fre frf fri frk fro frp frr frs fse fsf fsi fsk fso fsp fsr fss i-f ie- iee ief iei iek iep ier ies ife iff ifi ifo ifp ifr ifs iie iif iii iio iip iir iis ike ikf iki ikk iko ikr iks io- ioe iof ioi ioo iop ior ios ipe ipf ipi ipo ipp ipr ips ir- ire irf iri irk iro irp irr irs is- ise isf isi isk iso isp isr iss ke- kee kef kei kek keo kep ker kes kff kfi kfo kfs kie kif kii kik kio kip kir kis kke kki kkk kkp kkr kks koe kof koi kok koo kop kor kos kpe kpf kpi kpk kpo kpp kpr kps krf kri krk kro krp krr krs kse ksf ksi ksk kso ksp ksr kss o-i oee oef oei oeo oep oer oes of- ofe off ofi ofo ofp ofr ofs oie oif oii oik oio oip oir ois oke oki okk oko okp okr oks oo- oof ooi ook ooo oop oor oos op- ope opf opi opk opo opp opr ops or- ore orf ori ork oro orp orr ors os- ose osf osi osk oso osp osr oss p-p pee pef pei pek peo pep per pes pfe pff pfi pfk pfo pfp pfr pfs pie pif pii pik pio pip pir pis pke pkf pki pko pkp pkr pks poe pof poi pok poo pop por pos ppe ppf ppi ppk ppo ppp ppr pps pre prf pri prk pro prp prr prs ps- pse psf psi psk pso psp psr pss re- ree ref rei rek reo rep rer res rfe rff rfi rfk rfo rfp rfr rfs rie rif rii rik rio rip rir ris rke rkf rkk rko rkp rks roe rof roi rok roo rop ror ros rpe rpf rpi rpk rpo rpp rpr rps rrf rri rrk rrp rrr rrs rse rsf rsi rsk rso rsp rsr rss se- see sef sei sek seo sep ser ses sfe sff sfi sfk sfo sfp sfr sfs sie sif sii sik sio sip sir sis sk- ske skf ski skk sko skp skr sks soe sof soi sok soo sop sor sos spe spf spi spk spo spp spr sps sr- sre srf sri srk sro srp srr srs ss- sse ssf ssi ssk sso ssp ssr sss