-er bbb bbd bbe bbr bdb bdd bde bdr bdv be- beb bed bee ber bev brb brd bre brr brv bvb bvd bve bvr bvv dbb dbd dbe dbr dbv ddb ddd dde ddr de- deb ded dee der dev drb drd dre drr drv dvb dvd dve dvr ebb ebd ebe ebr ebv ed- edb edd ede edr eeb eed eee eer eev erb erd ere err erv evb evd eve evr evv rbb rbd rbe rbr rdb rdd rde rdr rdv re- reb red ree rer rev rrb rrd rrr rvb rvd rve rvr rvv v-e vbd vbr vbv vdb vdd vde vdr vdv veb ved vee ver vrb vrd vre vrr vvb vvr vvv