-al -ol a-a a-b a-c aaa aab aac aad aaf aak aal aao ab- aba abb abc abd abf abk abl abo ac- aca acb acc acd acf ack acl aco ad- ada adb adc add adf adk adl ado af- afa afb afc afd aff afk afl afo aka akb akc akd akk akl ako al- ala alb alc ald alf alk all alo aoa aob aoc aod aof aok aol aoo baa bab bac bad baf bak bal bao bba bbb bbc bbd bbf bbk bbl bbo bca bcb bcc bcd bcf bck bcl bco bda bdb bdc bdd bdf bdk bdl bdo bfa bfb bfc bfd bff bfl bfo bka bkb bkc bkf bkk bkl bko bla blb blc bld blf blk bll blo boa bob boc bod bof bok bol boo c-- caa cab cac cad caf cak cal cao cba cbb cbc cbd cbf cbk cbl cbo cca ccb ccc ccd ccf cck ccl cco cda cdb cdc cdd cdf cdk cdl cdo cfa cfb cfc cfd cff cfk cfl cfo cka ckb ckc ckd cko cl- cla clb clc cld clf clk cll clo co- coa cob coc cod cof cok col coo daa dab dac dad daf dak dal dao dba dbb dbc dbd dbf dbk dbl dbo dca dcb dcc dcd dcf dck dcl dco dda ddb ddc ddd ddf ddk ddl ddo dfa dfb dfc dfd dff dfk dfl dfo dka dkb dkc dkk dkl dko dl- dla dlb dlc dld dlf dlk dll dlo doa dob doc dod dof dok dol doo faa fab fac fad faf fak fal fao fba fbb fbc fbd fbf fbk fbl fbo fca fcb fcc fcd fcf fck fcl fco fda fdb fdc fdd fdf fdk fdl fdo ffa ffc ffd fff ffk ffl ffo fka fkb fkc fkf fkk fkl fla flb flc fld flf fll flo foa fob foc fof fok fol foo ka- kaa kab kac kad kaf kak kal kao kba kbb kbc kbd kbf kbk kbl kbo kca kcb kcc kcd kck kcl kda kdb kdc kdf kdk kdl kdo kfa kfc kfd kff kfo kkb kkc kkk kkl kl- kla klb klc kld klf klo koa kob koc kod kof kok kol koo la- laa lab lac lad laf lak lal lao lba lbb lbc lbd lbf lbk lbl lbo lca lcb lcc lcd lcf lck lcl lco lda ldb ldc ldd ldf ldk ldl ldo lfa lfb lfc lfd lff lfk lfl lfo lka lkb lkl lla llb llc lld llf llk lll llo loa lob loc lod lof lok lol loo oaa oab oac oad oaf oak oal oao ob- oba obb obc obd obf obk obl obo oc- oca ocb occ ocd ocf ock ocl oco oda odb odc odd odf odl odo of- ofa ofb ofc ofd off ofl ofo oka okb okc okd okk okl oko ola olb olc old olf olk oll olo oo- ooa oob ooc ood oof ook ool ooo