-al a-a a-b a-c aaa aab aac aae aal aas ab- aba abb abc abe abl abs ac- aca acb acc ace acl acs aea aeb aec aee ael aes al- ala alb alc ale all als as- asa asb asc ase asl ass baa bab bac bae bal bas bba bbb bbc bbe bbl bbs bca bcb bcc bce bcl bcs be- bea beb bec bee bel bes bla blb blc ble bll bls bsa bsb bsc bse bsl bss c-- caa cab cac cae cal cas cba cbb cbc cbe cbl cbs cca ccb ccc cce ccl ccs ce- cea ceb cec cee cel ces cl- cla clb clc cle cll cls csa csb csc cse csl css eaa eab eac eae eal eas eba ebb ebc ebe ebl ebs ec- eca ecb ecc ece ecl ecs eea eeb eec eee eel ees ela elb elc ele ell els es- esa esb esc ese esl ess la- laa lab lac lae lal las lba lbb lbc lbe lbl lbs lca lcb lcc lce lcl lcs lea leb lec lee lel les lla llb llc lle lll lls lsa lsb lsc lse lsl lss saa sab sac sae sal sas sba sbb sbc sbe sbl sbs sca scb scc sce scl scs se- sea seb sec see sel ses sla slb slc sle sll sls ss- ssa ssb ssc sse ssl sss