-er a-a a-b a-t aaa aab aae aak aam aao aar aat ab- aba abb abe abk abm abo abr abt aea aeb aee aek aem aeo aer aet aka akb ake akk akm ako akr ama amb ame amk amm amo amr amt aoa aob aoe aok aom aoo aor aot ar- ara arb are ark arm aro arr art at- ata atb ate atm ato atr att baa bab bae bak bam bao bar bat bba bbb bbe bbk bbm bbo bbr bbt be- bea beb bee bek bem beo ber bet bka bkb bke bkk bkm bko bkr bkt bma bmb bme bmk bmm bmo bmr bmt boa bob boe bok bom boo bor bot bra brb bre brk brm bro brr brt bta btb bte btk btm bto btr btt eaa eab eae eak eam eao ear eat eba ebb ebe ebk ebm ebo ebr ebt eea eeb eee eek eem eeo eer eet eka ekb eke eko ekr ekt em- ema emb eme emk emm emo emr emt eo- eoa eob eoe eok eom eoo eor eot era erb ere erk erm ero err ert eta etb ete etk etm eto etr ett k-t ka- kaa kab kae kak kam kao kar kat kba kbb kbe kbk kbm kbo kbr ke- kea keb kee kek kem keo ker ket kkb kke kkk kkm kkr kkt kma kmb kme kmk kmm kmo kmt koa kob koe kok kom koo kor kot kra krk kro krr krt kta ktb kte ktk ktm kto ktr ktt m-o m-r maa mab mae mak mam mao mar mat mba mbb mbe mbk mbm mbo mbr mbt mea meb mee mek mem meo mer met mka mkb mke mkk mkm mko mkr mkt mma mmb mme mmk mmm mmo mmr mmt moa mob moe mok mom moo mor mot mra mrb mre mrk mrm mro mrr mrt mta mtb mte mtk mtm mto mtr mtt oaa oab oae oak oam oao oar oat ob- oba obb obe obk obm obo obr obt oea oeb oee oem oeo oer oet oka okb oke okk oko okr om- oma omb ome omm omo omr omt oo- ooa oob ook oom ooo oor oot or- ora orb ore ork orm oro orr ort ot- ota otb ote otk otm oto otr ott ra- raa rab rae rak ram rao rar rat rba rbb rbe rbk rbm rbo rbr rbt re- rea reb ree rek rem reo rer ret rkb rke rkk rkm rko rkt rma rmb rme rmm rmo rmr rmt roa rob roe rok rom roo ror rot rra rrb rrk rrm rrr rrt rta rtb rte rtk rtm rto rtr rtt taa tab tae tak tam tao tar tat tba tbb tbe tbk tbm tbo tbr tbt te- tea teb tee tek tem teo ter tet tka tkb tke tkk tkm tko tkr tkt tma tmb tme tmk tmm tmo tmr tmt to- toa tob toe tok tom too tor tot tra trb tre trk trm tro trr trt tta ttb tte ttk ttm tto ttr ttt