-er a-a a-b a-t aaa aab aad aae aak aar aat ab- aba abb abd abe abk abr abt ad- ada adb add ade adk adr adt aea aeb aed aee aek aer aet aka akb akd ake akk akr ar- ara arb ard are ark arr art at- ata atb atd ate atr att baa bab bad bae bak bar bat bba bbb bbd bbe bbk bbr bbt bda bdb bdd bde bdk bdr bdt be- bea beb bed bee bek ber bet bka bkb bke bkk bkr bkt bra brb brd bre brk brr brt bta btb btd bte btk btr btt daa dab dad dae dak dar dat dba dbb dbd dbe dbk dbr dbt dda ddb ddd dde ddk ddr ddt de- dea deb ded dee dek der det dka dkb dke dkk dkr dkt dra drb drd dre drk drr drt dta dtb dtd dte dtk dtr dtt eaa eab ead eae eak ear eat eba ebb ebd ebe ebk ebr ebt ed- eda edb edd ede edk edr edt eea eeb eed eee eek eer eet eka ekb ekd eke ekr ekt era erb erd ere erk err ert eta etb etd ete etk etr ett k-t ka- kaa kab kad kae kak kar kat kba kbb kbd kbe kbk kbr kda kdb kde kdk kdr kdt ke- kea keb ked kee kek ker ket kkb kke kkk kkr kkt kra krd krk krr krt kta ktb kte ktk ktr ktt ra- raa rab rad rae rak rar rat rba rbb rbd rbe rbk rbr rbt rda rdb rdd rde rdr rdt re- rea reb red ree rek rer ret rkb rke rkk rkt rra rrb rrd rrk rrr rrt rta rtb rtd rte rtk rtr rtt taa tab tad tae tak tar tat tba tbb tbd tbe tbk tbr tbt tda tdb tdd tde tdk tdr tdt te- tea teb ted tee tek ter tet tka tkb tke tkk tkr tkt tra trb trd tre trk trr trt tta ttb ttd tte ttk ttr ttt