-al -ol a-a a-b a-c aaa aab aac aak aal aao aar ab- aba abb abc abk abl abo abr ac- aca acb acc ack acl aco acr aka akb akc akk akl ako akr al- ala alb alc alk all alo alr aoa aob aoc aok aol aoo aor ar- ara arb arc ark arl aro arr baa bab bac bak bal bao bar bba bbb bbc bbk bbl bbo bbr bca bcb bcc bck bcl bco bcr bka bkb bkc bkk bkl bko bkr bla blb blc blk bll blo blr boa bob boc bok bol boo bor bra brb brk brl bro brr c-- caa cab cac cak cal cao car cba cbb cbc cbk cbl cbo cbr cca ccb ccc cck ccl cco ccr cka ckb ckc cko cl- cla clb clc clk cll clo clr co- coa cob coc cok col coo cor cra crb crc crk crl cro crr ka- kaa kab kac kak kal kao kar kba kbb kbc kbk kbl kbo kbr kca kcb kcc kck kcl kcr kkb kkc kkk kkl kkr kl- kla klb klc klo klr koa kob koc kok kol koo kor kra krc krk krl kro krr la- laa lab lac lak lal lao lar lba lbb lbc lbk lbl lbo lbr lca lcb lcc lck lcl lco lcr lka lkb lkl lkr lla llb llc llk lll llo llr loa lob loc lok lol loo lor lra lrb lrc lrk lro lrr oaa oab oac oak oal oao oar ob- oba obb obc obk obl obo obr oc- oca ocb occ ock ocl oco ocr oka okb okc okk okl oko okr ola olb olc olk oll olo oo- ooa oob ooc ook ool ooo oor or- ora orb orc ork orl oro orr ra- raa rab rac rak ral rao rar rba rbb rbc rbk rbl rbo rbr rca rcb rcc rcl rco rcr rkb rkc rkk rko rla rlc rll rlo rlr roa rob roc rok rol roo ror rra rrb rrc rrk rrl rrr