a-a a-b a-t aaa aab aad aaf aak aan aar aat ab- aba abb abd abf abk abn abr abt ad- ada adb add adf adk adn adr adt af- afa afb afd aff afk afn afr aft aka akb akd akk akn akr an- ana anb and anf ank ann anr ant ar- ara arb ard arf ark arn arr art at- ata atb atd atf atn atr att baa bab bad baf bak ban bar bat bba bbb bbd bbf bbk bbn bbr bbt bda bdb bdd bdf bdk bdr bdt bfa bfb bfd bff bfn bfr bft bka bkb bkf bkk bkn bkr bkt bna bnb bnd bnf bnk bnn bnr bnt bra brb brd brf brk brn brr brt bta btb btd btf btk btn btr btt daa dab dad daf dak dan dar dat dba dbb dbd dbf dbk dbn dbr dbt dda ddb ddd ddf ddk ddn ddr ddt dfa dfb dfd dff dfk dfn dfr dft dka dkb dkk dkr dkt dna dnb dnd dnf dnk dnn dnr dnt dra drb drd drk drn drr drt dta dtb dtd dtf dtk dtn dtr dtt faa fab fad faf fak fan far fat fba fbb fbd fbf fbk fbn fbr fbt fda fdb fdd fdf fdk fdn fdr fdt ffa ffd fff ffk ffn ffr fft fka fkb fkf fkk fkt fna fnb fnd fnf fnk fnn fnr fnt fra frb frd frf frk frn frr frt fta ftb ftd ftf ftk ftn ftr ftt k-t ka- kaa kab kad kaf kak kan kar kat kba kbb kbd kbf kbk kbn kbr kda kdb kdf kdk kdr kdt kfa kfd kff kkb kkk kkn kkr kkt kn- kna knd knf knk knn knr knt kra krd krf krk krn krr krt kta ktb ktf ktk ktn ktr ktt naa nab nad naf nak nan nar nat nba nbb nbd nbf nbk nbn nbr nbt nda ndb ndd ndf ndk ndn ndr ndt nfa nfb nfd nff nfk nfn nfr nft nka nkf nkk nkn nkr nkt nna nnb nnf nnk nnn nnt nra nrb nrd nrf nrk nrn nrr nrt nta ntb ntd ntf ntk ntn ntr ntt ra- raa rab rad raf rak ran rar rat rba rbb rbd rbf rbk rbn rbr rbt rda rdb rdd rdf rdn rdr rdt rfa rfb rfd rff rfk rfn rfr rft rkb rkf rkk rkt rna rnb rnd rnn rnr rnt rra rrb rrd rrf rrk rrn rrr rrt rta rtb rtd rtf rtk rtn rtr rtt taa tab tad taf tak tan tar tat tba tbb tbd tbf tbk tbn tbr tbt tda tdb tdd tdf tdk tdn tdr tdt tfa tfb tfd tff tfk tfn tfr tft tka tkb tkk tkr tkt tna tnb tnd tnf tnk tnn tnr tnt tra trb trd trf trk trn trr trt tta ttb ttd ttf ttk ttn ttr ttt