bbb bbc bbe bbk bbs bcb bcc bce bck bcs be- beb bec bee bek bes bkb bkc bke bkk bks bsb bsc bse bsk bss c-- cbb cbc cbe cbk cbs ccb ccc cce cck ccs ce- ceb cec cee cek ces ckb ckc cks csb csc cse csk css ebb ebc ebe ebk ebs ec- ecb ecc ece eck ecs eeb eec eee eek ees ekb ekc eke eks es- esb esc ese esk ess kbb kbc kbe kbk kbs kcb kcc kce kck kcs ke- keb kec kee kek kes kkb kkc kke kkk kks ksb ksc kse ksk kss sbb sbc sbe sbk sbs scb scc sce sck scs se- seb sec see sek ses sk- skb skc ske skk sks ss- ssb ssc sse ssk sss