-al a-a a-b a-c aaa aab aac aal aas ab- aba abb abc abl abs ac- aca acb acc acl acs al- ala alb alc all als as- asa asb asc asl ass baa bab bac bal bas bba bbb bbc bbl bbs bca bcb bcc bcl bcs bla blb blc bll bls bsa bsb bsc bsl bss c-- caa cab cac cal cas cba cbb cbc cbl cbs cca ccb ccc ccl ccs cl- cla clb clc cll cls csa csb csc csl css la- laa lab lac lal las lba lbb lbc lbl lbs lca lcb lcc lcl lcs lla llb llc lll lls lsa lsb lsc lsl lss saa sab sac sal sas sba sbb sbc sbl sbs sca scb scc scl scs sla slb slc sll sls ss- ssa ssb ssc ssl sss