-al -ol a-a a-b a-c a-t aaa aab aac aak aal aao aar aat ab- aba abb abc abk abl abo abr abt ac- aca acb acc ack acl aco acr act aka akb akc akk akl ako akr al- ala alb alc alk all alo alr alt aoa aob aoc aok aol aoo aor aot ar- ara arb arc ark arl aro arr art at- ata atb atc atl ato atr att baa bab bac bak bal bao bar bat bba bbb bbc bbk bbl bbo bbr bbt bca bcb bcc bck bcl bco bcr bct bka bkb bkc bkk bkl bko bkr bkt bla blb blc blk bll blo blr blt boa bob boc bok bol boo bor bot bra brb brk brl bro brr brt bta btb btc btk btl bto btr btt c-- caa cab cac cak cal cao car cat cba cbb cbc cbk cbl cbo cbr cbt cca ccb ccc cck ccl cco ccr cct cka ckb ckc cko ckt cl- cla clb clc clk cll clo clr clt co- coa cob coc cok col coo cor cot cra crb crc crk crl cro crr crt cta ctb ctc ctk ctl cto ctr ctt k-t ka- kaa kab kac kak kal kao kar kat kba kbb kbc kbk kbl kbo kbr kca kcb kcc kck kcl kcr kct kkb kkc kkk kkl kkr kkt kl- kla klb klc klo klr klt koa kob koc kok kol koo kor kot kra krc krk krl kro krr krt kta ktb ktc ktk ktl kto ktr ktt la- laa lab lac lak lal lao lar lat lba lbb lbc lbk lbl lbo lbr lbt lca lcb lcc lck lcl lco lcr lct lka lkb lkl lkr lkt lla llb llc llk lll llo llr llt loa lob loc lok lol loo lor lot lra lrb lrc lrk lro lrr lrt lta ltb ltc ltk ltl lto ltr ltt oaa oab oac oak oal oao oar oat ob- oba obb obc obk obl obo obr obt oc- oca ocb occ ock ocl oco ocr oct oka okb okc okk okl oko okr ola olb olc olk oll olo olt oo- ooa oob ooc ook ool ooo oor oot or- ora orb orc ork orl oro orr ort ot- ota otb otc otk otl oto otr ott ra- raa rab rac rak ral rao rar rat rba rbb rbc rbk rbl rbo rbr rbt rca rcb rcc rcl rco rcr rct rkb rkc rkk rko rkt rla rlc rll rlo rlr rlt roa rob roc rok rol roo ror rot rra rrb rrc rrk rrl rrr rrt rta rtb rtc rtk rtl rto rtr rtt taa tab tac tak tal tao tar tat tba tbb tbc tbk tbl tbo tbr tbt tca tcb tcc tck tcl tco tcr tct tka tkb tkc tkk tkl tko tkr tkt tla tlc tlk tll tlo tlr tlt to- toa tob toc tok tol too tor tot tra trb trc trk trl tro trr trt tta ttb ttc ttk ttl tto ttr ttt