-er a-a a-b a-t aaa aab aae aag aak aar aat ab- aba abb abe abg abk abr abt aea aeb aee aeg aek aer aet ag- aga agb age agg agk agr agt aka akb ake akg akk akr ar- ara arb are arg ark arr art at- ata atb ate atg atr att baa bab bae bag bak bar bat bba bbb bbe bbg bbk bbr bbt be- bea beb bee beg bek ber bet bga bgb bge bgg bgk bgr bgt bka bkb bke bkg bkk bkr bkt bra brb bre brg brk brr brt bta btb bte btg btk btr btt eaa eab eae eag eak ear eat eba ebb ebe ebg ebk ebr ebt eea eeb eee eeg eek eer eet ega egb ege egg egr egt eka ekb eke ekg ekr ekt era erb ere erg erk err ert eta etb ete etg etk etr ett gaa gab gae gag gak gar gat gba gbe gbg gbk gbr gbt ge- gea geb gee geg gek ger get gga ggb ggg ggr ggt gka gkb gkt gra grb gre grg grk grr grt gta gtb gte gtg gtk gtr gtt k-t ka- kaa kab kae kag kak kar kat kba kbb kbe kbk kbr ke- kea keb kee keg kek ker ket kga kgb kkb kke kkk kkr kkt kra krg krk krr krt kta ktb kte ktg ktk ktr ktt ra- raa rab rae rag rak rar rat rba rbb rbe rbg rbk rbr rbt re- rea reb ree reg rek rer ret rga rgb rge rgg rgk rgr rgt rkb rke rkg rkk rkt rra rrb rrg rrk rrr rrt rta rtb rte rtg rtk rtr rtt taa tab tae tag tak tar tat tba tbb tbe tbg tbk tbr tbt te- tea teb tee teg tek ter tet tga tgb tge tgg tgk tgr tgt tka tkb tke tkg tkk tkr tkt tra trb tre trg trk trr trt tta ttb tte ttg ttk ttr ttt