bbb bbc bbk bbn bbo bbr bbt bcb bcc bck bcn bco bcr bct bkb bkc bkk bkn bko bkr bkt bnb bnc bnk bnn bno bnr bnt bob boc bok bon boo bor bot brb brk brn bro brr brt btb btc btk btn bto btr btt c-- cbb cbc cbk cbn cbo cbr cbt ccb ccc cck ccn cco ccr cct ckb ckc cko ckt cn- cnb cnc cnn cno cnr cnt co- cob coc cok con coo cor cot crb crc crk crn cro crr crt ctb ctc ctk ctn cto ctr ctt k-t kbb kbc kbk kbn kbo kbr kcb kcc kck kcn kcr kct kkb kkc kkk kkn kkr kkt kn- knc knk knn kno knr knt kob koc kok kon koo kor kot krc krk krn kro krr krt ktb ktc ktk ktn kto ktr ktt nbb nbc nbk nbn nbo nbr nbt ncb ncc nck ncn nco ncr nct nkc nkk nkn nko nkr nkt nnb nnc nnk nnn nno nnt no- nob noc nok non noo nor not nrb nrc nrk nrn nro nrr nrt ntb ntc ntk ntn nto ntr ntt ob- obb obc obk obn obo obr obt oc- ocb occ ock ocn oco ocr oct okb okc okk oko okr on- onb onc onk onn ono onr ont oo- oob ooc ook oon ooo oor oot or- orb orc ork orn oro orr ort ot- otb otc otk otn oto otr ott rbb rbc rbk rbn rbo rbr rbt rcb rcc rcn rco rcr rct rkb rkc rkk rko rkt rnb rnc rnn rno rnr rnt rob roc rok ron roo ror rot rrb rrc rrk rrn rrr rrt rtb rtc rtk rtn rto rtr rtt tbb tbc tbk tbn tbo tbr tbt tcb tcc tck tcn tco tcr tct tkb tkc tkk tko tkr tkt tnb tnc tnk tnn tno tnr tnt to- tob toc tok ton too tor tot trb trc trk trn tro trr trt ttb ttc ttk ttn tto ttr ttt