-er b-p bbb bbe bbf bbi bbk bbo bbp bbr be- beb bee bef bei bek beo bep ber bfb bfe bff bfi bfo bfp bfr bi- bib bie bif bii bik bio bip bir bkb bke bkf bkk bko bkp bkr bob boe bof boi bok boo bop bor bpb bpe bpf bpi bpo bpp bpr brb bre brf bri brk bro brp brr ebb ebe ebf ebi ebk ebo ebp ebr eeb eee eef eek eeo eep eer ef- efb efe eff efi efo efp efr eib eie eif eii eik eio eip eir ekb eke ekf eki eko ekp ekr eo- eob eoe eof eoi eok eoo eop eor ep- epb epe epf epi epo epp epr erb ere erf eri erk ero erp err fbb fbe fbf fbi fbk fbo fbp fbr feb fee fef fei fek feo fep fer ffe fff ffi ffk ffo ffp ffr fib fie fif fii fik fip fir fkb fkf fki fkk fkp fob foe fof foi fok foo fop for fpb fpe fpi fpk fpo fpp fpr frb fre frf fri frk fro frp frr i-f ibb ibe ibf ibi ibk ibo ibp ibr ie- iee ief iei iek iep ier ifb ife iff ifi ifo ifp ifr iib iie iif iii iio iip iir ikb ike ikf iki ikk iko ikr io- iob ioe iof ioi ioo iop ior ipb ipe ipf ipi ipo ipp ipr ir- irb ire irf iri irk iro irp irr kbb kbe kbf kbi kbk kbo kbp kbr ke- keb kee kef kei kek keo kep ker kff kfi kfo kib kie kif kii kik kio kip kir kkb kke kki kkk kkp kkr kob koe kof koi kok koo kop kor kpe kpf kpi kpk kpo kpp kpr krf kri krk kro krp krr o-i ob- obb obe obf obi obk obo obp obr oeb oee oef oei oeo oep oer of- ofb ofe off ofi ofo ofp ofr oib oie oif oii oik oio oip oir okb oke oki okk oko okp okr oo- oob oof ooi ook ooo oop oor op- opb ope opf opi opk opo opp opr or- orb ore orf ori ork oro orp orr p-p pbb pbe pbf pbi pbk pbo pbp pbr peb pee pef pei pek peo pep per pfb pfe pff pfi pfk pfo pfp pfr pib pie pif pii pik pio pip pir pkb pke pkf pki pko pkp pkr pob poe pof poi pok poo pop por ppb ppe ppf ppi ppk ppo ppp ppr prb pre prf pri prk pro prp prr rbb rbe rbf rbi rbk rbo rbp rbr re- reb ree ref rei rek reo rep rer rfb rfe rff rfi rfk rfo rfp rfr rib rie rif rii rik rio rip rir rkb rke rkf rkk rko rkp rob roe rof roi rok roo rop ror rpb rpe rpf rpi rpk rpo rpp rpr rrb rrf rri rrk rrp rrr