-al a-a a-b a-c aaa aab aac aae aaf aal aas ab- aba abb abc abe abf abl abs ac- aca acb acc ace acf acl acs aea aeb aec aee aef ael aes af- afa afb afc afe aff afl afs al- ala alb alc ale alf all als as- asa asb asc ase asf asl ass baa bab bac bae baf bal bas bba bbb bbc bbe bbf bbl bbs bca bcb bcc bce bcf bcl bcs be- bea beb bec bee bef bel bes bfa bfb bfc bfe bff bfl bfs bla blb blc ble blf bll bls bsa bsb bsc bse bsf bsl bss c-- caa cab cac cae caf cal cas cba cbb cbc cbe cbf cbl cbs cca ccb ccc cce ccf ccl ccs ce- cea ceb cec cee cef cel ces cfa cfb cfc cfe cff cfl cfs cl- cla clb clc cle clf cll cls csa csb csc cse csf csl css eaa eab eac eae eaf eal eas eba ebb ebc ebe ebf ebl ebs ec- eca ecb ecc ece ecf ecl ecs eea eeb eec eee eef eel ees ef- efa efb efc efe eff efl efs ela elb elc ele elf ell els es- esa esb esc ese esf esl ess faa fab fac fae faf fal fas fba fbb fbc fbe fbf fbl fbs fca fcb fcc fce fcf fcl fcs fea feb fec fee fef fel fes ffa ffc ffe fff ffl ffs fla flb flc fle flf fll fls fsa fsb fsc fse fsf fsl fss la- laa lab lac lae laf lal las lba lbb lbc lbe lbf lbl lbs lca lcb lcc lce lcf lcl lcs lea leb lec lee lef lel les lfa lfb lfc lfe lff lfl lfs lla llb llc lle llf lll lls lsa lsb lsc lse lsf lsl lss saa sab sac sae saf sal sas sba sbb sbc sbe sbf sbl sbs sca scb scc sce scf scl scs se- sea seb sec see sef sel ses sfa sfb sfc sfe sff sfl sfs sla slb slc sle slf sll sls ss- ssa ssb ssc sse ssf ssl sss