bbb bbc bbe bbk bbl bbs bcb bcc bce bck bcl bcs be- beb bec bee bek bel bes bkb bkc bke bkk bkl bks blb blc ble blk bll bls bsb bsc bse bsk bsl bss c-- cbb cbc cbe cbk cbl cbs ccb ccc cce cck ccl ccs ce- ceb cec cee cek cel ces ckb ckc cks cl- clb clc cle clk cll cls csb csc cse csk csl css ebb ebc ebe ebk ebl ebs ec- ecb ecc ece eck ecl ecs eeb eec eee eek eel ees ekb ekc eke ekl eks elb elc ele elk ell els es- esb esc ese esk esl ess kbb kbc kbe kbk kbl kbs kcb kcc kce kck kcl kcs ke- keb kec kee kek kel kes kkb kkc kke kkk kkl kks kl- klb klc kls ksb ksc kse ksk ksl kss lbb lbc lbe lbk lbl lbs lcb lcc lce lck lcl lcs leb lec lee lek lel les lkb lkl lks llb llc lle llk lll lls lsb lsc lse lsk lsl lss sbb sbc sbe sbk sbl sbs scb scc sce sck scl scs se- seb sec see sek sel ses sk- skb skc ske skk skl sks slb slc sle slk sll sls ss- ssb ssc sse ssk ssl sss