-er eee eef eek eeo eep eer ef- efe eff efi efo efp efr eie eif eii eik eio eip eir eke ekf eki eko ekp ekr eo- eoe eof eoi eok eoo eop eor ep- epe epf epi epo epp epr ere erf eri erk ero erp err fee fef fei fek feo fep fer ffe fff ffi ffk ffo ffp ffr fie fif fii fik fip fir fkf fki fkk fkp foe fof foi fok foo fop for fpe fpi fpk fpo fpp fpr fre frf fri frk fro frp frr i-f ie- iee ief iei iek iep ier ife iff ifi ifo ifp ifr iie iif iii iio iip iir ike ikf iki ikk iko ikr io- ioe iof ioi ioo iop ior ipe ipf ipi ipo ipp ipr ir- ire irf iri irk iro irp irr ke- kee kef kei kek keo kep ker kff kfi kfo kie kif kii kik kio kip kir kke kki kkk kkp kkr koe kof koi kok koo kop kor kpe kpf kpi kpk kpo kpp kpr krf kri krk kro krp krr o-i oee oef oei oeo oep oer of- ofe off ofi ofo ofp ofr oie oif oii oik oio oip oir oke oki okk oko okp okr oo- oof ooi ook ooo oop oor op- ope opf opi opk opo opp opr or- ore orf ori ork oro orp orr p-p pee pef pei pek peo pep per pfe pff pfi pfk pfo pfp pfr pie pif pii pik pio pip pir pke pkf pki pko pkp pkr poe pof poi pok poo pop por ppe ppf ppi ppk ppo ppp ppr pre prf pri prk pro prp prr re- ree ref rei rek reo rep rer rfe rff rfi rfk rfo rfp rfr rie rif rii rik rio rip rir rke rkf rkk rko rkp roe rof roi rok roo rop ror rpe rpf rpi rpk rpo rpp rpr rrf rri rrk rrp rrr