-al a-a a-b a-c aaa aab aac aad aaf aak aal aas ab- aba abb abc abd abf abk abl abs ac- aca acb acc acd acf ack acl acs ad- ada adb adc add adf adk adl ads af- afa afb afc afd aff afk afl afs aka akb akc akd akk akl aks al- ala alb alc ald alf alk all als as- asa asb asc asd asf ask asl ass baa bab bac bad baf bak bal bas bba bbb bbc bbd bbf bbk bbl bbs bca bcb bcc bcd bcf bck bcl bcs bda bdb bdc bdd bdf bdk bdl bds bfa bfb bfc bfd bff bfl bfs bka bkb bkc bkf bkk bkl bks bla blb blc bld blf blk bll bls bsa bsb bsc bsd bsf bsk bsl bss c-- caa cab cac cad caf cak cal cas cba cbb cbc cbd cbf cbk cbl cbs cca ccb ccc ccd ccf cck ccl ccs cda cdb cdc cdd cdf cdk cdl cds cfa cfb cfc cfd cff cfk cfl cfs cka ckb ckc ckd cks cl- cla clb clc cld clf clk cll cls csa csb csc csd csf csk csl css daa dab dac dad daf dak dal das dba dbb dbc dbd dbf dbk dbl dbs dca dcb dcc dcd dcf dck dcl dcs dda ddb ddc ddd ddf ddk ddl dds dfa dfb dfc dfd dff dfk dfl dfs dka dkb dkc dkk dkl dks dl- dla dlb dlc dld dlf dlk dll dls dsa dsb dsc dsd dsf dsk dsl dss faa fab fac fad faf fak fal fas fba fbb fbc fbd fbf fbk fbl fbs fca fcb fcc fcd fcf fck fcl fcs fda fdb fdc fdd fdf fdk fdl fds ffa ffc ffd fff ffk ffl ffs fka fkb fkc fkf fkk fkl fla flb flc fld flf fll fls fsa fsb fsc fsd fsf fsk fsl fss ka- kaa kab kac kad kaf kak kal kas kba kbb kbc kbd kbf kbk kbl kbs kca kcb kcc kcd kck kcl kcs kda kdb kdc kdf kdk kdl kds kfa kfc kfd kff kfs kkb kkc kkk kkl kks kl- kla klb klc kld klf kls ksa ksb ksc ksd ksf ksk ksl kss la- laa lab lac lad laf lak lal las lba lbb lbc lbd lbf lbk lbl lbs lca lcb lcc lcd lcf lck lcl lcs lda ldb ldc ldd ldf ldk ldl lds lfa lfb lfc lfd lff lfk lfl lfs lka lkb lkl lks lla llb llc lld llf llk lll lls lsa lsb lsc lsd lsf lsk lsl lss saa sab sac sad saf sak sal sas sba sbb sbc sbd sbf sbk sbl sbs sca scb scc scd scf sck scl scs sda sdb sdc sdd sdf sdk sdl sds sfa sfb sfc sfd sff sfk sfl sfs sk- ska skb skc skd skf skk skl sks sla slb slc sld slf slk sll sls ss- ssa ssb ssc ssd ssf ssk ssl sss