-er bbb bbd bbe bbk bbo bbr bbt bdb bdd bde bdk bdo bdr bdt be- beb bed bee bek beo ber bet bkb bke bkk bko bkr bkt bob bod boe bok boo bor bot brb brd bre brk bro brr brt btb btd bte btk bto btr btt dbb dbd dbe dbk dbo dbr dbt ddb ddd dde ddk ddo ddr ddt de- deb ded dee dek deo der det dkb dke dkk dko dkr dkt dob dod doe dok doo dor dot drb drd dre drk dro drr drt dtb dtd dte dtk dto dtr dtt ebb ebd ebe ebk ebo ebr ebt ed- edb edd ede edk edo edr edt eeb eed eee eek eeo eer eet ekb ekd eke eko ekr ekt eo- eob eod eoe eok eoo eor eot erb erd ere erk ero err ert etb etd ete etk eto etr ett k-t kbb kbd kbe kbk kbo kbr kdb kde kdk kdo kdr kdt ke- keb ked kee kek keo ker ket kkb kke kkk kkr kkt kob kod koe kok koo kor kot krd krk kro krr krt ktb kte ktk kto ktr ktt ob- obb obd obe obk obo obr obt odb odd ode odo odr odt oeb oed oee oeo oer oet okb okd oke okk oko okr oo- oob ood ook ooo oor oot or- orb ord ore ork oro orr ort ot- otb otd ote otk oto otr ott rbb rbd rbe rbk rbo rbr rbt rdb rdd rde rdo rdr rdt re- reb red ree rek reo rer ret rkb rke rkk rko rkt rob rod roe rok roo ror rot rrb rrd rrk rrr rrt rtb rtd rte rtk rto rtr rtt tbb tbd tbe tbk tbo tbr tbt tdb tdd tde tdk tdo tdr tdt te- teb ted tee tek teo ter tet tkb tke tkk tko tkr tkt to- tob tod toe tok too tor tot trb trd tre trk tro trr trt ttb ttd tte ttk tto ttr ttt