-er b-u bbb bbd bbe bbo bbr bbu bbx bdb bdd bde bdo bdr bdu bdx be- beb bed bee beo ber beu bex bob bod boe boo bor bou box brb brd bre bro brr bru brx bub bud bue buo bur buu bux bxb bxd bxo bxx dbb dbd dbe dbo dbr dbu dbx ddb ddd dde ddo ddr ddu ddx de- deb ded dee deo der deu dex dob dod doe doo dor dou dox drb drd dre dro drr dru drx dub dud due duo dur dux dxd dxo dxr dxx ebb ebd ebe ebo ebr ebu ebx ed- edb edd ede edo edr edu edx eeb eed eee eeo eer eex eo- eob eod eoe eoo eor eou erb erd ere ero err eru eu- eub eud eue eur eux ex- exd exe exo exr exu exx ob- obb obd obe obo obr obu obx odb odd ode odo odr odu oeb oed oee oeo oer oex oo- oob ood ooo oor oox or- orb ord ore oro orr oru orx ou- oud oue ouo our ox- oxb oxo oxx rbb rbd rbe rbo rbr rbu rbx rdb rdd rde rdo rdr rdu rdx re- reb red ree reo rer reu rex rob rod roe roo ror rou rox rrb rrd rrr rru rub rud rue ruo rur ruu rux rxr ubb ube ubo ubr ubu ubx udb udd ude udo udr udu udx ueb ued uee uer uob uod uoe uoo uor uox ur- urb urd ure uro urr uru urx uue uur uuu uxb uxo uxr uxu xbe xbr xbx xdb xde xdr xed xee xer xeu xex xod xoo xor xox xrd xrx xue xxo xxx