-er b-p bbb bbe bbi bbk bbo bbp bbr bbt be- beb bee bei bek beo bep ber bet bi- bib bie bii bik bio bip bir bit bkb bke bkk bko bkp bkr bkt bob boe boi bok boo bop bor bot bpb bpe bpi bpo bpp bpr bpt brb bre bri brk bro brp brr brt btb bte bti btk bto btp btr btt ebb ebe ebi ebk ebo ebp ebr ebt eeb eee eek eeo eep eer eet eib eie eii eik eio eip eir eit ekb eke eki eko ekp ekr ekt eo- eob eoe eoi eok eoo eop eor eot ep- epb epe epi epo epp epr ept erb ere eri erk ero erp err ert etb ete eti etk eto etp etr ett ibb ibe ibi ibk ibo ibp ibr ibt ie- iee iei iek iep ier iet iib iie iii iio iip iir iit ikb ike iki ikk iko ikr ikt io- iob ioe ioi ioo iop ior iot ipb ipe ipi ipo ipp ipr ipt ir- irb ire iri irk iro irp irr irt itb ite iti itk ito itp itt k-t kbb kbe kbi kbk kbo kbp kbr ke- keb kee kei kek keo kep ker ket kib kie kii kik kio kip kir kit kkb kke kki kkk kkp kkr kkt kob koe koi kok koo kop kor kot kpe kpi kpk kpo kpp kpr kpt kri krk kro krp krr krt ktb kte ktk kto ktp ktr ktt o-i ob- obb obe obi obk obo obp obr obt oeb oee oei oeo oep oer oet oib oie oii oik oio oip oir oit okb oke oki okk oko okp okr oo- oob ooi ook ooo oop oor oot op- opb ope opi opk opo opp opr opt or- orb ore ori ork oro orp orr ort ot- otb ote oti otk oto otp otr ott p-p pbb pbe pbi pbk pbo pbp pbr pbt peb pee pei pek peo pep per pet pib pie pii pik pio pip pir pit pkb pke pki pko pkp pkr pkt pob poe poi pok poo pop por pot ppb ppe ppi ppk ppo ppp ppr ppt prb pre pri prk pro prp prr prt pt- ptb pte pti ptk pto ptp ptr ptt rbb rbe rbi rbk rbo rbp rbr rbt re- reb ree rei rek reo rep rer ret rib rie rii rik rio rip rir rit rkb rke rkk rko rkp rkt rob roe roi rok roo rop ror rot rpb rpe rpi rpk rpo rpp rpr rpt rrb rri rrk rrp rrr rrt rtb rte rti rtk rto rtp rtr rtt tbb tbe tbi tbk tbo tbp tbr tbt te- teb tee tei tek teo tep ter tet tib tie tii tik tio tip tir tit tkb tke tkk tko tkp tkr tkt to- tob toe toi tok too top tor tot tpb tpe tpi tpk tpo tpp tpr tpt trb tre tri trk tro trp trr trt ttb tte tti ttk tto ttp ttr ttt