-er bbb bbd bbe bbo bbr bdb bdd bde bdo bdr bdv be- beb bed bee beo ber bev bob bod boe boo bor bov brb brd bre bro brr brv bvb bvd bve bvo bvr bvv dbb dbd dbe dbo dbr dbv ddb ddd dde ddo ddr de- deb ded dee deo der dev dob dod doe doo dor dov drb drd dre dro drr drv dvb dvd dve dvr ebb ebd ebe ebo ebr ebv ed- edb edd ede edo edr eeb eed eee eeo eer eev eo- eob eod eoe eoo eor erb erd ere ero err erv evb evd eve evo evr evv ob- obb obd obe obo obr obv odb odd ode odo odr odv oeb oed oee oeo oer oo- oob ood ooo oor oov or- orb ord ore oro orr orv ov- ovb ovd ove ovo ovv rbb rbd rbe rbo rbr rdb rdd rde rdo rdr rdv re- reb red ree reo rer rev rob rod roe roo ror rov rrb rrd rrr rvb rvd rve rvo rvr rvv v-e vbd vbo vbr vbv vdb vdd vde vdo vdr vdv veb ved vee veo ver vob vod voe voo vor vov vrb vrd vre vrr vvb vvo vvr vvv