-al -ol a-a a-b a-c aaa aab aac aak aal aao aas aax ab- aba abb abc abk abl abo abs abx ac- aca acb acc ack acl aco acs acx aka akb akc akk akl ako aks al- ala alb alc alk all alo als alx aoa aob aoc aok aol aoo aos aox as- asa asb asc ask asl aso ass asx ax- axa axk axl axo axs axx baa bab bac bak bal bao bas bax bba bbb bbc bbk bbl bbo bbs bbx bca bcb bcc bck bcl bco bcs bcx bka bkb bkc bkk bkl bko bks bkx bla blb blc blk bll blo bls blx boa bob boc bok bol boo bos box bsa bsb bsc bsk bsl bso bss bsx bxb bxl bxo bxx c-- caa cab cac cak cal cao cas cax cba cbb cbc cbk cbl cbo cbs cbx cca ccb ccc cck ccl cco ccs ccx cka ckb ckc cko cks ckx cl- cla clb clc clk cll clo cls clx co- coa cob coc cok col coo cos cox csa csb csc csk csl cso css csx cxc cxk cxl cxo cxs cxx ka- kaa kab kac kak kal kao kas kax kba kbb kbc kbk kbl kbo kbs kbx kca kcb kcc kck kcl kcs kcx kkb kkc kkk kkl kks kl- kla klb klc klo kls klx koa kob koc kok kol koo kos ksa ksb ksc ksk ksl kso kss kxl kxo la- laa lab lac lak lal lao las lax lba lbb lbc lbk lbl lbo lbs lbx lca lcb lcc lck lcl lco lcs lcx lka lkb lkl lks lla llb llc llk lll llo lls loa lob loc lok lol loo los lox lsa lsb lsc lsk lsl lso lss lxc lxo lxx oaa oab oac oak oal oao oas oax ob- oba obb obc obk obl obo obs obx oc- oca ocb occ ock ocl oco ocs ocx oka okb okc okk okl oko oks ola olb olc olk oll olo ols oo- ooa oob ooc ook ool ooo oos oox os- osa osb osc osk osl oso oss osx ox- oxa oxb oxc oxo oxx saa sab sac sak sal sao sas sax sba sbb sbc sbk sbl sbo sbs sbx sca scb scc sck scl sco scs scx sk- ska skb skc skk skl sko sks skx sla slb slc slk sll slo sls slx soa sob soc sok sol soo sos sox ss- ssa ssb ssc ssk ssl sso sss ssx sxc sxl sxs xaa xac xak xal xas xbc xbl xbx xcb xcl xcx xkb xkl xks xla xlb xls xoa xoc xok xoo xos xox xsa xsb xsc xsl xss xxl xxo xxx