-al -ol a-a a-b a-c aaa aab aac aak aal aao aax ab- aba abb abc abk abl abo abx ac- aca acb acc ack acl aco acx aka akb akc akk akl ako al- ala alb alc alk all alo alx aoa aob aoc aok aol aoo aox ax- axa axk axl axo axx baa bab bac bak bal bao bax bba bbb bbc bbk bbl bbo bbx bca bcb bcc bck bcl bco bcx bka bkb bkc bkk bkl bko bkx bla blb blc blk bll blo blx boa bob boc bok bol boo box bxb bxl bxo bxx c-- caa cab cac cak cal cao cax cba cbb cbc cbk cbl cbo cbx cca ccb ccc cck ccl cco ccx cka ckb ckc cko ckx cl- cla clb clc clk cll clo clx co- coa cob coc cok col coo cox cxc cxk cxl cxo cxx ka- kaa kab kac kak kal kao kax kba kbb kbc kbk kbl kbo kbx kca kcb kcc kck kcl kcx kkb kkc kkk kkl kl- kla klb klc klo klx koa kob koc kok kol koo kxl kxo la- laa lab lac lak lal lao lax lba lbb lbc lbk lbl lbo lbx lca lcb lcc lck lcl lco lcx lka lkb lkl lla llb llc llk lll llo loa lob loc lok lol loo lox lxc lxo lxx oaa oab oac oak oal oao oax ob- oba obb obc obk obl obo obx oc- oca ocb occ ock ocl oco ocx oka okb okc okk okl oko ola olb olc olk oll olo oo- ooa oob ooc ook ool ooo oox ox- oxa oxb oxc oxo oxx xaa xac xak xal xbc xbl xbx xcb xcl xcx xkb xkl xla xlb xoa xoc xok xoo xox xxl xxo xxx