bbb bbd bbk bbo bbr bbt bdb bdd bdk bdo bdr bdt bkb bkk bko bkr bkt bob bod bok boo bor bot brb brd brk bro brr brt btb btd btk bto btr btt dbb dbd dbk dbo dbr dbt ddb ddd ddk ddo ddr ddt dkb dkk dko dkr dkt dob dod dok doo dor dot drb drd drk dro drr drt dtb dtd dtk dto dtr dtt k-t kbb kbd kbk kbo kbr kdb kdk kdo kdr kdt kkb kkk kkr kkt kob kod kok koo kor kot krd krk kro krr krt ktb ktk kto ktr ktt ob- obb obd obk obo obr obt odb odd odo odr odt okb okd okk oko okr oo- oob ood ook ooo oor oot or- orb ord ork oro orr ort ot- otb otd otk oto otr ott rbb rbd rbk rbo rbr rbt rdb rdd rdo rdr rdt rkb rkk rko rkt rob rod rok roo ror rot rrb rrd rrk rrr rrt rtb rtd rtk rto rtr rtt tbb tbd tbk tbo tbr tbt tdb tdd tdk tdo tdr tdt tkb tkk tko tkr tkt to- tob tod tok too tor tot trb trd trk tro trr trt ttb ttd ttk tto ttr ttt