-al -ol a-a a-b a-c aaa aab aac aak aal aao ab- aba abb abc abk abl abo ac- aca acb acc ack acl aco aka akb akc akk akl ako al- ala alb alc alk all alo aoa aob aoc aok aol aoo baa bab bac bak bal bao bba bbb bbc bbk bbl bbo bca bcb bcc bck bcl bco bka bkb bkc bkk bkl bko bla blb blc blk bll blo boa bob boc bok bol boo c-- caa cab cac cak cal cao cba cbb cbc cbk cbl cbo cca ccb ccc cck ccl cco cka ckb ckc cko cl- cla clb clc clk cll clo co- coa cob coc cok col coo ka- kaa kab kac kak kal kao kba kbb kbc kbk kbl kbo kca kcb kcc kck kcl kkb kkc kkk kkl kl- kla klb klc klo koa kob koc kok kol koo la- laa lab lac lak lal lao lba lbb lbc lbk lbl lbo lca lcb lcc lck lcl lco lka lkb lkl lla llb llc llk lll llo loa lob loc lok lol loo oaa oab oac oak oal oao ob- oba obb obc obk obl obo oc- oca ocb occ ock ocl oco oka okb okc okk okl oko ola olb olc olk oll olo oo- ooa oob ooc ook ool ooo