c-- ccc ccd cce ccf cck ccl cdc cdd cde cdf cdk cdl ce- cec ced cee cef cek cel cfc cfd cfe cff cfk cfl ckc ckd cl- clc cld cle clf clk cll dcc dcd dce dcf dck dcl ddc ddd dde ddf ddk ddl de- dec ded dee def dek del dfc dfd dfe dff dfk dfl dkc dke dkk dkl dl- dlc dld dle dlf dlk dll ec- ecc ecd ece ecf eck ecl ed- edc edd ede edf edk edl eec eed eee eef eek eel ef- efc efd efe eff efl ekc ekd eke ekf ekl elc eld ele elf elk ell fcc fcd fce fcf fck fcl fdc fdd fde fdf fdk fdl fec fed fee fef fek fel ffc ffd ffe fff ffk ffl fkc fkf fkk fkl flc fld fle flf fll kcc kcd kce kck kcl kdc kde kdf kdk kdl ke- kec ked kee kef kek kel kfc kfd kff kkc kke kkk kkl kl- klc kld klf lcc lcd lce lcf lck lcl ldc ldd lde ldf ldk ldl lec led lee lef lek lel lfc lfd lfe lff lfk lfl lkl llc lld lle llf llk lll