-er b-p bbb bbd bbe bbk bbo bbp bbr bdb bdd bde bdk bdo bdp bdr be- beb bed bee bek beo bep ber bkb bke bkk bko bkp bkr bob bod boe bok boo bop bor bpb bpd bpe bpo bpp bpr brb brd bre brk bro brp brr dbb dbd dbe dbk dbo dbp dbr ddb ddd dde ddk ddo ddp ddr de- deb ded dee dek deo dep der dkb dke dkk dko dkp dkr dob dod doe dok doo dop dor dpb dpd dpe dpk dpo dpp dpr drb drd dre drk dro drp drr ebb ebd ebe ebk ebo ebp ebr ed- edb edd ede edk edo edp edr eeb eed eee eek eeo eep eer ekb ekd eke eko ekp ekr eo- eob eod eoe eok eoo eop eor ep- epb epd epe epo epp epr erb erd ere erk ero erp err kbb kbd kbe kbk kbo kbp kbr kdb kde kdk kdo kdp kdr ke- keb ked kee kek keo kep ker kkb kke kkk kkp kkr kob kod koe kok koo kop kor kpd kpe kpk kpo kpp kpr krd krk kro krp krr ob- obb obd obe obk obo obp obr odb odd ode odo odp odr oeb oed oee oeo oep oer okb okd oke okk oko okp okr oo- oob ood ook ooo oop oor op- opb opd ope opk opo opp opr or- orb ord ore ork oro orp orr p-p pbb pbd pbe pbk pbo pbp pbr pdb pdd pde pdk pdo pdp pdr peb ped pee pek peo pep per pkb pkd pke pko pkp pkr pob pod poe pok poo pop por ppb ppd ppe ppk ppo ppp ppr prb prd pre prk pro prp prr rbb rbd rbe rbk rbo rbp rbr rdb rdd rde rdo rdp rdr re- reb red ree rek reo rep rer rkb rke rkk rko rkp rob rod roe rok roo rop ror rpb rpd rpe rpk rpo rpp rpr rrb rrd rrk rrp rrr