a-a a-b a-c a-t aaa aab aac aak aan aao aar aat ab- aba abb abc abk abn abo abr abt ac- aca acb acc ack acn aco acr act aka akb akc akk akn ako akr an- ana anb anc ank ann ano anr ant aoa aob aoc aok aon aoo aor aot ar- ara arb arc ark arn aro arr art at- ata atb atc atn ato atr att baa bab bac bak ban bao bar bat bba bbb bbc bbk bbn bbo bbr bbt bca bcb bcc bck bcn bco bcr bct bka bkb bkc bkk bkn bko bkr bkt bna bnb bnc bnk bnn bno bnr bnt boa bob boc bok bon boo bor bot bra brb brk brn bro brr brt bta btb btc btk btn bto btr btt c-- caa cab cac cak can cao car cat cba cbb cbc cbk cbn cbo cbr cbt cca ccb ccc cck ccn cco ccr cct cka ckb ckc cko ckt cn- cna cnb cnc cnn cno cnr cnt co- coa cob coc cok con coo cor cot cra crb crc crk crn cro crr crt cta ctb ctc ctk ctn cto ctr ctt k-t ka- kaa kab kac kak kan kao kar kat kba kbb kbc kbk kbn kbo kbr kca kcb kcc kck kcn kcr kct kkb kkc kkk kkn kkr kkt kn- kna knc knk knn kno knr knt koa kob koc kok kon koo kor kot kra krc krk krn kro krr krt kta ktb ktc ktk ktn kto ktr ktt naa nab nac nak nan nao nar nat nba nbb nbc nbk nbn nbo nbr nbt nca ncb ncc nck ncn nco ncr nct nka nkc nkk nkn nko nkr nkt nna nnb nnc nnk nnn nno nnt no- noa nob noc nok non noo nor not nra nrb nrc nrk nrn nro nrr nrt nta ntb ntc ntk ntn nto ntr ntt oaa oab oac oak oan oao oar oat ob- oba obb obc obk obn obo obr obt oc- oca ocb occ ock ocn oco ocr oct oka okb okc okk oko okr on- ona onb onc onk onn ono onr ont oo- ooa oob ooc ook oon ooo oor oot or- ora orb orc ork orn oro orr ort ot- ota otb otc otk otn oto otr ott ra- raa rab rac rak ran rao rar rat rba rbb rbc rbk rbn rbo rbr rbt rca rcb rcc rcn rco rcr rct rkb rkc rkk rko rkt rna rnb rnc rnn rno rnr rnt roa rob roc rok ron roo ror rot rra rrb rrc rrk rrn rrr rrt rta rtb rtc rtk rtn rto rtr rtt taa tab tac tak tan tao tar tat tba tbb tbc tbk tbn tbo tbr tbt tca tcb tcc tck tcn tco tcr tct tka tkb tkc tkk tko tkr tkt tna tnb tnc tnk tnn tno tnr tnt to- toa tob toc tok ton too tor tot tra trb trc trk trn tro trr trt tta ttb ttc ttk ttn tto ttr ttt