a-a a-b a-c a-t aaa aab aac aaf aan aao aar aat ab- aba abb abc abf abn abo abr abt ac- aca acb acc acf acn aco acr act af- afa afb afc aff afn afo afr aft an- ana anb anc anf ann ano anr ant aoa aob aoc aof aon aoo aor aot ar- ara arb arc arf arn aro arr art at- ata atb atc atf atn ato atr att baa bab bac baf ban bao bar bat bba bbb bbc bbf bbn bbo bbr bbt bca bcb bcc bcf bcn bco bcr bct bfa bfb bfc bff bfn bfo bfr bft bna bnb bnc bnf bnn bno bnr bnt boa bob boc bof bon boo bor bot bra brb brf brn bro brr brt bta btb btc btf btn bto btr btt c-- caa cab cac caf can cao car cat cba cbb cbc cbf cbn cbo cbr cbt cca ccb ccc ccf ccn cco ccr cct cfa cfb cfc cff cfn cfo cfr cft cn- cna cnb cnc cnf cnn cno cnr cnt co- coa cob coc cof con coo cor cot cra crb crc crf crn cro crr crt cta ctb ctc ctf ctn cto ctr ctt faa fab fac faf fan fao far fat fba fbb fbc fbf fbn fbo fbr fbt fca fcb fcc fcf fcn fco fcr fct ffa ffc fff ffn ffo ffr fft fna fnb fnc fnf fnn fnr fnt foa fob foc fof fon foo for fot fra frb frc frf frn fro frr frt fta ftb ftc ftf ftn fto ftr ftt naa nab nac naf nan nao nar nat nba nbb nbc nbf nbn nbo nbr nbt nca ncb ncc ncf ncn nco ncr nct nfa nfb nfc nff nfn nfo nfr nft nna nnb nnc nnf nnn nno nnt no- noa nob noc nof non noo nor not nra nrb nrc nrf nrn nro nrr nrt nta ntb ntc ntf ntn nto ntr ntt oaa oab oac oaf oan oao oar oat ob- oba obb obc obf obn obo obr obt oc- oca ocb occ ocf ocn oco ocr oct of- ofa ofb ofc off ofn ofo ofr oft on- ona onb onc onf onn ono onr ont oo- ooa oob ooc oof oon ooo oor oot or- ora orb orc orf orn oro orr ort ot- ota otb otc otf otn oto otr ott ra- raa rab rac raf ran rao rar rat rba rbb rbc rbf rbn rbo rbr rbt rca rcb rcc rcf rcn rco rcr rct rfa rfb rfc rff rfn rfo rfr rft rna rnb rnc rnn rno rnr rnt roa rob roc rof ron roo ror rot rra rrb rrc rrf rrn rrr rrt rta rtb rtc rtf rtn rto rtr rtt taa tab tac taf tan tao tar tat tba tbb tbc tbf tbn tbo tbr tbt tca tcb tcc tcf tcn tco tcr tct tfa tfb tfc tff tfn tfo tfr tft tna tnb tnc tnf tnn tno tnr tnt to- toa tob toc tof ton too tor tot tra trb trc trf trn tro trr trt tta ttb ttc ttf ttn tto ttr ttt