-er a-a a-b a-c a-t aaa aab aac aae aaf aak aao aar aat ab- aba abb abc abe abf abk abo abr abt ac- aca acb acc ace acf ack aco acr act aea aeb aec aee aef aek aeo aer aet af- afa afb afc afe aff afk afo afr aft aka akb akc ake akk ako akr aoa aob aoc aoe aof aok aoo aor aot ar- ara arb arc are arf ark aro arr art at- ata atb atc ate atf ato atr att baa bab bac bae baf bak bao bar bat bba bbb bbc bbe bbf bbk bbo bbr bbt bca bcb bcc bce bcf bck bco bcr bct be- bea beb bec bee bef bek beo ber bet bfa bfb bfc bfe bff bfo bfr bft bka bkb bkc bke bkf bkk bko bkr bkt boa bob boc boe bof bok boo bor bot bra brb bre brf brk bro brr brt bta btb btc bte btf btk bto btr btt c-- caa cab cac cae caf cak cao car cat cba cbb cbc cbe cbf cbk cbo cbr cbt cca ccb ccc cce ccf cck cco ccr cct ce- cea ceb cec cee cef cek ceo cer cet cfa cfb cfc cfe cff cfk cfo cfr cft cka ckb ckc cko ckt co- coa cob coc coe cof cok coo cor cot cra crb crc cre crf crk cro crr crt cta ctb ctc cte ctf ctk cto ctr ctt eaa eab eac eae eaf eak eao ear eat eba ebb ebc ebe ebf ebk ebo ebr ebt ec- eca ecb ecc ece ecf eck eco ecr ect eea eeb eec eee eef eek eeo eer eet ef- efa efb efc efe eff efo efr eft eka ekb ekc eke ekf eko ekr ekt eo- eoa eob eoc eoe eof eok eoo eor eot era erb erc ere erf erk ero err ert eta etb etc ete etf etk eto etr ett faa fab fac fae faf fak fao far fat fba fbb fbc fbe fbf fbk fbo fbr fbt fca fcb fcc fce fcf fck fco fcr fct fea feb fec fee fef fek feo fer fet ffa ffc ffe fff ffk ffo ffr fft fka fkb fkc fkf fkk fkt foa fob foc foe fof fok foo for fot fra frb frc fre frf frk fro frr frt fta ftb ftc fte ftf ftk fto ftr ftt k-t ka- kaa kab kac kae kaf kak kao kar kat kba kbb kbc kbe kbf kbk kbo kbr kca kcb kcc kce kck kcr kct ke- kea keb kec kee kef kek keo ker ket kfa kfc kff kfo kkb kkc kke kkk kkr kkt koa kob koc koe kof kok koo kor kot kra krc krf krk kro krr krt kta ktb ktc kte ktf ktk kto ktr ktt oaa oab oac oae oaf oak oao oar oat ob- oba obb obc obe obf obk obo obr obt oc- oca ocb occ ocf ock oco ocr oct oea oeb oec oee oef oeo oer oet of- ofa ofb ofc ofe off ofo ofr oft oka okb okc oke okk oko okr oo- ooa oob ooc oof ook ooo oor oot or- ora orb orc ore orf ork oro orr ort ot- ota otb otc ote otf otk oto otr ott ra- raa rab rac rae raf rak rao rar rat rba rbb rbc rbe rbf rbk rbo rbr rbt rca rcb rcc rce rcf rco rcr rct re- rea reb rec ree ref rek reo rer ret rfa rfb rfc rfe rff rfk rfo rfr rft rkb rkc rke rkf rkk rko rkt roa rob roc roe rof rok roo ror rot rra rrb rrc rrf rrk rrr rrt rta rtb rtc rte rtf rtk rto rtr rtt taa tab tac tae taf tak tao tar tat tba tbb tbc tbe tbf tbk tbo tbr tbt tca tcb tcc tce tcf tck tco tcr tct te- tea teb tec tee tef tek teo ter tet tfa tfb tfc tfe tff tfk tfo tfr tft tka tkb tkc tke tkk tko tkr tkt to- toa tob toc toe tof tok too tor tot tra trb trc tre trf trk tro trr trt tta ttb ttc tte ttf ttk tto ttr ttt