a-a a-c aaa aac aae aam aas ac- aca acc ace acm acs aea aec aee aem aes ama amc ame amm ams as- asa asc ase asm ass c-- caa cac cae cam cas cca ccc cce ccm ccs ce- cea cec cee cem ces cma cmc cme cmm cms csa csc cse csm css eaa eac eae eam eas ec- eca ecc ece ecm ecs eea eec eee eem ees em- ema emc eme emm ems es- esa esc ese esm ess maa mac mae mam mas mc- mca mcc mce mcm mcs mea mec mee mem mes mma mmc mme mmm mms msa msc mse msm mss saa sac sae sam sas sca scc sce scm scs se- sea sec see sem ses sma smc sme smm sms ss- ssa ssc sse ssm sss