-er b-p bbb bbe bbo bbp bbr be- beb bee beo bep ber bev bob boe boo bop bor bov bpb bpe bpo bpp bpr bpv brb bre bro brp brr brv bvb bve bvo bvp bvr bvv ebb ebe ebo ebp ebr ebv eeb eee eeo eep eer eev eo- eob eoe eoo eop eor ep- epb epe epo epp epr erb ere ero erp err erv evb eve evo evp evr evv ob- obb obe obo obp obr obv oeb oee oeo oep oer oo- oob ooo oop oor oov op- opb ope opo opp opr opv or- orb ore oro orp orr orv ov- ovb ove ovo ovp ovv p-p pbb pbe pbo pbp pbr peb pee peo pep per pev pob poe poo pop por pov ppb ppe ppo ppp ppr ppv prb pre pro prp prr prv pvb pve pvo pvp pvr pvv rbb rbe rbo rbp rbr re- reb ree reo rep rer rev rob roe roo rop ror rov rpb rpe rpo rpp rpr rpv rrb rrp rrr rvb rve rvo rvp rvr rvv v-e vbo vbr vbv veb vee veo vep ver vob voe voo vop vor vov vpb vpe vpo vpp vpr vrb vre vrp vrr vvb vvo vvr vvv