a-a a-b a-t aaa aab aak aan aar aat ab- aba abb abk abn abr abt aka akb akk akn akr an- ana anb ank ann anr ant ar- ara arb ark arn arr art at- ata atb atn atr att baa bab bak ban bar bat bba bbb bbk bbn bbr bbt bka bkb bkk bkn bkr bkt bna bnb bnk bnn bnr bnt bra brb brk brn brr brt bta btb btk btn btr btt k-t ka- kaa kab kak kan kar kat kba kbb kbk kbn kbr kkb kkk kkn kkr kkt kn- kna knk knn knr knt kra krk krn krr krt kta ktb ktk ktn ktr ktt naa nab nak nan nar nat nba nbb nbk nbn nbr nbt nka nkk nkn nkr nkt nna nnb nnk nnn nnt nra nrb nrk nrn nrr nrt nta ntb ntk ntn ntr ntt ra- raa rab rak ran rar rat rba rbb rbk rbn rbr rbt rkb rkk rkt rna rnb rnn rnr rnt rra rrb rrk rrn rrr rrt rta rtb rtk rtn rtr rtt taa tab tak tan tar tat tba tbb tbk tbn tbr tbt tka tkb tkk tkr tkt tna tnb tnk tnn tnr tnt tra trb trk trn trr trt tta ttb ttk ttn ttr ttt