-er a-a a-b a-t aaa aab aae aag aak aao aar aat ab- aba abb abe abg abk abo abr abt aea aeb aee aeg aek aeo aer aet ag- aga agb age agg agk ago agr agt aka akb ake akg akk ako akr aoa aob aoe aog aok aoo aor aot ar- ara arb are arg ark aro arr art at- ata atb ate atg ato atr att baa bab bae bag bak bao bar bat bba bbb bbe bbg bbk bbo bbr bbt be- bea beb bee beg bek beo ber bet bga bgb bge bgg bgk bgo bgr bgt bka bkb bke bkg bkk bko bkr bkt boa bob boe bog bok boo bor bot bra brb bre brg brk bro brr brt bta btb bte btg btk bto btr btt eaa eab eae eag eak eao ear eat eba ebb ebe ebg ebk ebo ebr ebt eea eeb eee eeg eek eeo eer eet ega egb ege egg ego egr egt eka ekb eke ekg eko ekr ekt eo- eoa eob eoe eog eok eoo eor eot era erb ere erg erk ero err ert eta etb ete etg etk eto etr ett gaa gab gae gag gak gao gar gat gba gbe gbg gbk gbo gbr gbt ge- gea geb gee geg gek geo ger get gga ggb ggg ggo ggr ggt gka gkb gko gkt goa gob goe gog gok goo gor got gra grb gre grg grk gro grr grt gta gtb gte gtg gtk gto gtr gtt k-t ka- kaa kab kae kag kak kao kar kat kba kbb kbe kbk kbo kbr ke- kea keb kee keg kek keo ker ket kga kgb kgo kkb kke kkk kkr kkt koa kob koe kog kok koo kor kot kra krg krk kro krr krt kta ktb kte ktg ktk kto ktr ktt oaa oab oae oag oak oao oar oat ob- oba obb obe obg obk obo obr obt oea oeb oee oeg oeo oer oet oga oge ogg ogo ogt oka okb oke okg okk oko okr oo- ooa oob oog ook ooo oor oot or- ora orb ore org ork oro orr ort ot- ota otb ote otg otk oto otr ott ra- raa rab rae rag rak rao rar rat rba rbb rbe rbg rbk rbo rbr rbt re- rea reb ree reg rek reo rer ret rga rgb rge rgg rgk rgo rgr rgt rkb rke rkg rkk rko rkt roa rob roe rog rok roo ror rot rra rrb rrg rrk rrr rrt rta rtb rte rtg rtk rto rtr rtt taa tab tae tag tak tao tar tat tba tbb tbe tbg tbk tbo tbr tbt te- tea teb tee teg tek teo ter tet tga tgb tge tgg tgk tgo tgr tgt tka tkb tke tkg tkk tko tkr tkt to- toa tob toe tog tok too tor tot tra trb tre trg trk tro trr trt tta ttb tte ttg ttk tto ttr ttt