b-u bbb bbc bbk bbn bbo bbr bbt bbu bcb bcc bck bcn bco bcr bct bcu bkb bkc bkk bkn bko bkr bkt bnb bnc bnk bnn bno bnr bnt bnu bob boc bok bon boo bor bot bou brb brk brn bro brr brt bru btb btc btk btn bto btr btt btu bub buc buk bun buo bur but buu c-- cbb cbc cbk cbn cbo cbr cbt cbu ccb ccc cck ccn cco ccr cct ccu ckb ckc cko ckt cn- cnb cnc cnn cno cnr cnt cnu co- cob coc cok con coo cor cot cou crb crc crk crn cro crr crt cru ctb ctc ctk ctn cto ctr ctt ctu cub cuc cuk cun cuo cur cut cuu k-t kbb kbc kbk kbn kbo kbr kbu kcb kcc kck kcn kcr kct kcu kkb kkc kkk kkn kkr kkt kku kn- knc knk knn kno knr knt knu kob koc kok kon koo kor kot kou krc krk krn kro krr krt kru ktb ktc ktk ktn kto ktr ktt ktu kub kuc kuk kun kur kut kuu nbb nbc nbk nbn nbo nbr nbt nbu ncb ncc nck ncn nco ncr nct ncu nkc nkk nkn nko nkr nkt nku nnb nnc nnk nnn nno nnt nnu no- nob noc nok non noo nor not nou nrb nrc nrk nrn nro nrr nrt nru ntb ntc ntk ntn nto ntr ntt ntu nub nuc nuk nun nuo nur nut nuu ob- obb obc obk obn obo obr obt obu oc- ocb occ ock ocn oco ocr oct ocu okb okc okk oko okr oku on- onb onc onk onn ono onr ont onu oo- oob ooc ook oon ooo oor oot or- orb orc ork orn oro orr ort oru ot- otb otc otk otn oto otr ott otu ou- ouc ouk oun ouo our out rbb rbc rbk rbn rbo rbr rbt rbu rcb rcc rcn rco rcr rct rcu rkb rkc rkk rko rkt rku rnb rnc rnn rno rnr rnt rnu rob roc rok ron roo ror rot rou rrb rrc rrk rrn rrr rrt rru rtb rtc rtk rtn rto rtr rtt rtu rub ruc ruk run ruo rur rut ruu tbb tbc tbk tbn tbo tbr tbt tbu tcb tcc tck tcn tco tcr tct tcu tkb tkc tkk tko tkr tkt tnb tnc tnk tnn tno tnr tnt to- tob toc tok ton too tor tot tou trb trc trk trn tro trr trt tru ttb ttc ttk ttn tto ttr ttt ttu tub tuc tuk tun tuo tur tut tuu ubb ubc ubk ubn ubo ubr ubt ubu ucb ucc uck ucn uco ucr uct ucu ukb ukc ukk ukn ukr uku un- unb unc unk unn uno unr unt unu uob uoc uok uon uoo uor uot ur- urb urc urk urn uro urr urt uru utb utc utk utn uto utr utt utu uuc uun uur uut uuu