bbb bbc bbe bbk bbn bcb bcc bce bck bcn be- beb bec bee bek ben bkb bkc bke bkk bkn bnb bnc bne bnk bnn c-- cbb cbc cbe cbk cbn ccb ccc cce cck ccn ce- ceb cec cee cek cen ckb ckc cn- cnb cnc cne cnn ebb ebc ebe ebk ebn ec- ecb ecc ece eck ecn eeb eec eee eek een ekb ekc eke en- enb enc ene enk enn kbb kbc kbe kbk kbn kcb kcc kce kck kcn ke- keb kec kee kek ken kkb kkc kke kkk kkn kn- knc kne knk knn nbb nbc nbe nbk nbn ncb ncc nce nck ncn ne- neb nec nee nek nen nkc nke nkk nkn nnb nnc nne nnk nnn