-er b-p bbb bbd bbe bbo bbp bbr bdb bdd bde bdo bdp bdr be- beb bed bee beo bep ber bob bod boe boo bop bor bpb bpd bpe bpo bpp bpr brb brd bre bro brp brr dbb dbd dbe dbo dbp dbr ddb ddd dde ddo ddp ddr de- deb ded dee deo dep der dob dod doe doo dop dor dpb dpd dpe dpo dpp dpr drb drd dre dro drp drr ebb ebd ebe ebo ebp ebr ed- edb edd ede edo edp edr eeb eed eee eeo eep eer eo- eob eod eoe eoo eop eor ep- epb epd epe epo epp epr erb erd ere ero erp err ob- obb obd obe obo obp obr odb odd ode odo odp odr oeb oed oee oeo oep oer oo- oob ood ooo oop oor op- opb opd ope opo opp opr or- orb ord ore oro orp orr p-p pbb pbd pbe pbo pbp pbr pdb pdd pde pdo pdp pdr peb ped pee peo pep per pob pod poe poo pop por ppb ppd ppe ppo ppp ppr prb prd pre pro prp prr rbb rbd rbe rbo rbp rbr rdb rdd rde rdo rdp rdr re- reb red ree reo rep rer rob rod roe roo rop ror rpb rpd rpe rpo rpp rpr rrb rrd rrp rrr