bbb bbc bbe bbk bbs bbt bcb bcc bce bck bcs bct be- beb bec bee bek bes bet bkb bkc bke bkk bks bkt bsb bsc bse bsk bss bst btb btc bte btk bts btt c-- cbb cbc cbe cbk cbs cbt ccb ccc cce cck ccs cct ce- ceb cec cee cek ces cet ckb ckc cks ckt csb csc cse csk css cst ctb ctc cte ctk cts ctt ebb ebc ebe ebk ebs ebt ec- ecb ecc ece eck ecs ect eeb eec eee eek ees eet ekb ekc eke eks ekt es- esb esc ese esk ess est etb etc ete etk ets ett k-t kbb kbc kbe kbk kbs kcb kcc kce kck kcs kct ke- keb kec kee kek kes ket kkb kkc kke kkk kks kkt ksb ksc kse ksk kss kst ktb ktc kte ktk kts ktt sbb sbc sbe sbk sbs sbt scb scc sce sck scs sct se- seb sec see sek ses set sk- skb skc ske skk sks skt ss- ssb ssc sse ssk sss sst stb stc ste stk sts stt tbb tbc tbe tbk tbs tbt tcb tcc tce tck tcs tct te- teb tec tee tek tes tet tkb tkc tke tkk tks tkt tsb tsc tse tsk tss tst ttb ttc tte ttk tts ttt