bbb bbc bbk bbn bbr bcb bcc bck bcn bcr bkb bkc bkk bkn bkr bnb bnc bnk bnn bnr brb brk brn brr c-- cbb cbc cbk cbn cbr ccb ccc cck ccn ccr ckb ckc cn- cnb cnc cnn cnr crb crc crk crn crr kbb kbc kbk kbn kbr kcb kcc kck kcn kcr kkb kkc kkk kkn kkr kn- knc knk knn knr krc krk krn krr nbb nbc nbk nbn nbr ncb ncc nck ncn ncr nkc nkk nkn nkr nnb nnc nnk nnn nrb nrc nrk nrn nrr rbb rbc rbk rbn rbr rcb rcc rcn rcr rkb rkc rkk rnb rnc rnn rnr rrb rrc rrk rrn rrr