c-- ccc cce ccf cck ccl ccs ce- cec cee cef cek cel ces cfc cfe cff cfk cfl cfs ckc cks cl- clc cle clf clk cll cls csc cse csf csk csl css ec- ecc ece ecf eck ecl ecs eec eee eef eek eel ees ef- efc efe eff efl efs ekc eke ekf ekl eks elc ele elf elk ell els es- esc ese esf esk esl ess fcc fce fcf fck fcl fcs fec fee fef fek fel fes ffc ffe fff ffk ffl ffs fkc fkf fkk fkl flc fle flf fll fls fsc fse fsf fsk fsl fss kcc kce kck kcl kcs ke- kec kee kef kek kel kes kfc kff kfs kkc kke kkk kkl kks kl- klc klf kls ksc kse ksf ksk ksl kss lcc lce lcf lck lcl lcs lec lee lef lek lel les lfc lfe lff lfk lfl lfs lkl lks llc lle llf llk lll lls lsc lse lsf lsk lsl lss scc sce scf sck scl scs se- sec see sef sek sel ses sfc sfe sff sfk sfl sfs sk- skc ske skf skk skl sks slc sle slf slk sll sls ss- ssc sse ssf ssk ssl sss