b-u bbb bbc bbk bbn bbr bbs bbu bcb bcc bck bcn bcr bcs bcu bkb bkc bkk bkn bkr bks bnb bnc bnk bnn bnr bns bnu brb brk brn brr brs bru bsb bsc bsk bsn bsr bss bsu bub buc buk bun bur bus buu c-- cbb cbc cbk cbn cbr cbs cbu ccb ccc cck ccn ccr ccs ccu ckb ckc cks cn- cnb cnc cnn cnr cns cnu crb crc crk crn crr crs cru csb csc csk csn csr css csu cub cuc cuk cun cur cus cuu kbb kbc kbk kbn kbr kbs kbu kcb kcc kck kcn kcr kcs kcu kkb kkc kkk kkn kkr kks kku kn- knc knk knn knr knu krc krk krn krr krs kru ksb ksc ksk ksn ksr kss ksu kub kuc kuk kun kur kus kuu nbb nbc nbk nbn nbr nbs nbu ncb ncc nck ncn ncr ncs ncu nkc nkk nkn nkr nks nku nnb nnc nnk nnn nns nnu nrb nrc nrk nrn nrr nrs nru nsb nsc nsk nsn nsr nss nsu nub nuc nuk nun nur nus nuu rbb rbc rbk rbn rbr rbs rbu rcb rcc rcn rcr rcs rcu rkb rkc rkk rks rku rnb rnc rnn rnr rns rnu rrb rrc rrk rrn rrr rrs rru rsb rsc rsk rsn rsr rss rsu rub ruc ruk run rur rus ruu sbb sbc sbk sbn sbr sbs sbu scb scc sck scn scr scs scu sk- skb skc skk skr sks sku snb snc snk snn snr sns snu sr- srb src srk srn srr srs ss- ssb ssc ssk ssn ssr sss ssu sub suc suk sun sur sus suu ubb ubc ubk ubn ubr ubs ubu ucb ucc uck ucn ucr ucs ucu ukb ukc ukk ukn ukr uku un- unb unc unk unn unr uns unu ur- urb urc urk urn urr urs uru usb usc usk usn usr uss usu uuc uun uur uus uuu