bbb bbc bbe bbk bbt bcb bcc bce bck bct be- beb bec bee bek bet bkb bkc bke bkk bkt btb btc bte btk btt c-- cbb cbc cbe cbk cbt ccb ccc cce cck cct ce- ceb cec cee cek cet ckb ckc ckt ctb ctc cte ctk ctt ebb ebc ebe ebk ebt ec- ecb ecc ece eck ect eeb eec eee eek eet ekb ekc eke ekt etb etc ete etk ett k-t kbb kbc kbe kbk kcb kcc kce kck kct ke- keb kec kee kek ket kkb kkc kke kkk kkt ktb ktc kte ktk ktt tbb tbc tbe tbk tbt tcb tcc tce tck tct te- teb tec tee tek tet tkb tkc tke tkk tkt ttb ttc tte ttk ttt