c-- ccc cce ccf ccl ccs ce- cec cee cef cel ces cfc cfe cff cfl cfs cl- clc cle clf cll cls csc cse csf csl css ec- ecc ece ecf ecl ecs eec eee eef eel ees ef- efc efe eff efl efs elc ele elf ell els es- esc ese esf esl ess fcc fce fcf fcl fcs fec fee fef fel fes ffc ffe fff ffl ffs flc fle flf fll fls fsc fse fsf fsl fss lcc lce lcf lcl lcs lec lee lef lel les lfc lfe lff lfl lfs llc lle llf lll lls lsc lse lsf lsl lss scc sce scf scl scs se- sec see sef sel ses sfc sfe sff sfl sfs slc sle slf sll sls ss- ssc sse ssf ssl sss