-ol c-- ccc ccf cck ccl cco ccs cfc cff cfk cfl cfo cfs ckc cko cks cl- clc clf clk cll clo cls co- coc cof cok col coo cos csc csf csk csl cso css fcc fcf fck fcl fco fcs ffc fff ffk ffl ffo ffs fkc fkf fkk fkl flc flf fll flo fls foc fof fok fol foo fos fsc fsf fsk fsl fso fss kcc kck kcl kcs kfc kff kfo kfs kkc kkk kkl kks kl- klc klf klo kls koc kof kok kol koo kos ksc ksf ksk ksl kso kss lcc lcf lck lcl lco lcs lfc lff lfk lfl lfo lfs lkl lks llc llf llk lll llo lls loc lof lok lol loo los lsc lsf lsk lsl lso lss oc- occ ocf ock ocl oco ocs of- ofc off ofl ofo ofs okc okk okl oko oks olc olf olk oll olo ols oo- ooc oof ook ool ooo oos os- osc osf osk osl oso oss scc scf sck scl sco scs sfc sff sfk sfl sfo sfs sk- skc skf skk skl sko sks slc slf slk sll slo sls soc sof sok sol soo sos ss- ssc ssf ssk ssl sso sss