c-- ccc cce ccf cck ccl ce- cec cee cef cek cel cfc cfe cff cfk cfl ckc cl- clc cle clf clk cll ec- ecc ece ecf eck ecl eec eee eef eek eel ef- efc efe eff efl ekc eke ekf ekl elc ele elf elk ell fcc fce fcf fck fcl fec fee fef fek fel ffc ffe fff ffk ffl fkc fkf fkk fkl flc fle flf fll kcc kce kck kcl ke- kec kee kef kek kel kfc kff kkc kke kkk kkl kl- klc klf lcc lce lcf lck lcl lec lee lef lek lel lfc lfe lff lfk lfl lkl llc lle llf llk lll