a-a a-b a-t aaa aab aad aaf aan aar aat ab- aba abb abd abf abn abr abt ad- ada adb add adf adn adr adt af- afa afb afd aff afn afr aft an- ana anb and anf ann anr ant ar- ara arb ard arf arn arr art at- ata atb atd atf atn atr att baa bab bad baf ban bar bat bba bbb bbd bbf bbn bbr bbt bda bdb bdd bdf bdr bdt bfa bfb bfd bff bfn bfr bft bna bnb bnd bnf bnn bnr bnt bra brb brd brf brn brr brt bta btb btd btf btn btr btt daa dab dad daf dan dar dat dba dbb dbd dbf dbn dbr dbt dda ddb ddd ddf ddn ddr ddt dfa dfb dfd dff dfn dfr dft dna dnb dnd dnf dnn dnr dnt dra drb drd drn drr drt dta dtb dtd dtf dtn dtr dtt faa fab fad faf fan far fat fba fbb fbd fbf fbn fbr fbt fda fdb fdd fdf fdn fdr fdt ffa ffd fff ffn ffr fft fna fnb fnd fnf fnn fnr fnt fra frb frd frf frn frr frt fta ftb ftd ftf ftn ftr ftt naa nab nad naf nan nar nat nba nbb nbd nbf nbn nbr nbt nda ndb ndd ndf ndn ndr ndt nfa nfb nfd nff nfn nfr nft nna nnb nnf nnn nnt nra nrb nrd nrf nrn nrr nrt nta ntb ntd ntf ntn ntr ntt ra- raa rab rad raf ran rar rat rba rbb rbd rbf rbn rbr rbt rda rdb rdd rdf rdn rdr rdt rfa rfb rfd rff rfn rfr rft rna rnb rnd rnn rnr rnt rra rrb rrd rrf rrn rrr rrt rta rtb rtd rtf rtn rtr rtt taa tab tad taf tan tar tat tba tbb tbd tbf tbn tbr tbt tda tdb tdd tdf tdn tdr tdt tfa tfb tfd tff tfn tfr tft tna tnb tnd tnf tnn tnr tnt tra trb trd trf trn trr trt tta ttb ttd ttf ttn ttr ttt