-er a-a a-b a-t aaa aab aae aak aan aar aat ab- aba abb abe abk abn abr abt aea aeb aee aek aen aer aet aka akb ake akk akn akr an- ana anb ane ank ann anr ant ar- ara arb are ark arn arr art at- ata atb ate atn atr att baa bab bae bak ban bar bat bba bbb bbe bbk bbn bbr bbt be- bea beb bee bek ben ber bet bka bkb bke bkk bkn bkr bkt bna bnb bne bnk bnn bnr bnt bra brb bre brk brn brr brt bta btb bte btk btn btr btt eaa eab eae eak ean ear eat eba ebb ebe ebk ebn ebr ebt eea eeb eee eek een eer eet eka ekb eke ekr ekt en- ena enb ene enk enn enr ent era erb ere erk ern err ert eta etb ete etk etn etr ett k-t ka- kaa kab kae kak kan kar kat kba kbb kbe kbk kbn kbr ke- kea keb kee kek ken ker ket kkb kke kkk kkn kkr kkt kn- kna kne knk knn knr knt kra krk krn krr krt kta ktb kte ktk ktn ktr ktt naa nab nae nak nan nar nat nba nbb nbe nbk nbn nbr nbt ne- nea neb nee nek nen ner net nka nke nkk nkn nkr nkt nna nnb nne nnk nnn nnt nra nrb nre nrk nrn nrr nrt nta ntb nte ntk ntn ntr ntt ra- raa rab rae rak ran rar rat rba rbb rbe rbk rbn rbr rbt re- rea reb ree rek ren rer ret rkb rke rkk rkt rna rnb rnn rnr rnt rra rrb rrk rrn rrr rrt rta rtb rte rtk rtn rtr rtt taa tab tae tak tan tar tat tba tbb tbe tbk tbn tbr tbt te- tea teb tee tek ten ter tet tka tkb tke tkk tkr tkt tna tnb tne tnk tnn tnr tnt tra trb tre trk trn trr trt tta ttb tte ttk ttn ttr ttt