-er a-a a-b a-c aaa aab aac aae aaf aak aar ab- aba abb abc abe abf abk abr ac- aca acb acc ace acf ack acr aea aeb aec aee aef aek aer af- afa afb afc afe aff afk afr aka akb akc ake akk akr ar- ara arb arc are arf ark arr baa bab bac bae baf bak bar bba bbb bbc bbe bbf bbk bbr bca bcb bcc bce bcf bck bcr be- bea beb bec bee bef bek ber bfa bfb bfc bfe bff bfr bka bkb bkc bke bkf bkk bkr bra brb bre brf brk brr c-- caa cab cac cae caf cak car cba cbb cbc cbe cbf cbk cbr cca ccb ccc cce ccf cck ccr ce- cea ceb cec cee cef cek cer cfa cfb cfc cfe cff cfk cfr cka ckb ckc cra crb crc cre crf crk crr eaa eab eac eae eaf eak ear eba ebb ebc ebe ebf ebk ebr ec- eca ecb ecc ece ecf eck ecr eea eeb eec eee eef eek eer ef- efa efb efc efe eff efr eka ekb ekc eke ekf ekr era erb erc ere erf erk err faa fab fac fae faf fak far fba fbb fbc fbe fbf fbk fbr fca fcb fcc fce fcf fck fcr fea feb fec fee fef fek fer ffa ffc ffe fff ffk ffr fka fkb fkc fkf fkk fra frb frc fre frf frk frr ka- kaa kab kac kae kaf kak kar kba kbb kbc kbe kbf kbk kbr kca kcb kcc kce kck kcr ke- kea keb kec kee kef kek ker kfa kfc kff kkb kkc kke kkk kkr kra krc krf krk krr ra- raa rab rac rae raf rak rar rba rbb rbc rbe rbf rbk rbr rca rcb rcc rce rcf rcr re- rea reb rec ree ref rek rer rfa rfb rfc rfe rff rfk rfr rkb rkc rke rkf rkk rra rrb rrc rrf rrk rrr

a-ak a-be aaaa aaab aaac aaae aaaf aaar aaba aabb aabc aaca aacb aacc aace aacf aack aacr aaea aaec aafa aafb aafc aaff aaka aake aara aarc aare abaa abab abac abae abaf abak abar abb- abba abbb abbe abbr abca abcb abcc abcf abcr abec abee aber abff abra abrc acaa acab acac acae acar acba acca accc acce accf ace- acea acec acek acer acfc acfe acke acr- acra acrc acre acrr aeac aeaf aecb aeer aeka aer- aera aerc afaa afak afar afca afcb afcc afee afek afer affa affc afka afkr afr- afra afrc afre akaa akae akar akca akee aker akka akr- akra akre arab arac arae araf arak arar arba arbe arc- arca arce area arec aree aref arek arfa arfb arfc arff arka arke arr- arra arrc arre arrk arrr baaa baaf baak baar baba babb babe babr bac- baca bacc bace back baek baer bafc baff bak- baka bake bakr bar- bara barb barc bare barf bark barr bbbb bbeb bbfc bbrc bcaa bcar bcbc bcca bccc bcec bcer bcfc bcra beaf beak bear beba bebb bebe beca beck beeb beef beek beer befa befe beff beka beke bera berc bere berk berr bfca brab brac brae braf brak brca brcb brce brea breb brec bree bref brek brer brfc brka brkb brrr caaa caab caac caaf caba cabe cabf cac- caca cacc cace cack cacr caec caer cafa cafb cafc cafe caff caka cake cara carb carc care carf cark carr cbac cbar cbbc cbca cbcc cbce cbcr cbea cbec cbee cbef cber cbfb cbfc cbka cbkr cbre ccaa ccab ccac ccaf ccar ccba ccbc ccca cccb cccc cccf ccee ccfa ccfc ccff ccra ccrc ccre ccrf ceac cear ceba cec- ceca cece ceeb ceec cef- cefa cefc ceke cer- cera cerc cere cerf cfaa cfab cfac cfae cfar cfbc cfbr cfca cfcb cfcf cffb cffr cfra cfrb cfre ckac ckbc ckbe ckck cker ckfr ckrc crab crac craf crar crbc crca crcc crce crcr cre- crea creb crec cree crfc crkc eaaf eaba eaca eacc eaec eafb eara earb eare ebac ebba ebbc ebbr ebcc eber ebfc ecaa ecac ecar ecbc ecbe ecca eccb eccc ecce ecef ecfa ecfc ecfr ecka ecra ecrc ecrf ecrr eeca eeea eeee eefa eefe eeka eeke eera eerc efab efbr efca effa efke eka- ekab ekeb ekek eker ekfc ekka eraf erba erbb erbe erca ercc erce ereb erec erer erfc erke erra errc erre f--k faaa faac faba fabe faca facc face fack faeb fafa fafc fafe faff fake fara farb farc fare fark farr fbar fcab fcar fcba fcca fccf fcra feaf feak fear feba fece feck feeb feek feer fefc fefe feff feke fera ferb ferc fere ferk ferr ffar ffcc ffee ffff ffrr fkab frab frac frae frak frbc frcc frea free frfc kaaa kaab kaaf kaak kaar kaba kabb kabc kabe kabf kabr kacb kacc kace kaer kafa kafc kafe kaff kafr kaka kakc kake kakk kara karb kare karf kark karr kbaa kbab kbac kbae kbak kbar kbba kbbb kbbc kbbe kbbf kbbk kbbr kbca kbcb kbce kbck kbcr kbeb kbec kbee kbef kbek kber kbfb kbfc kbff kbfk kbfr kbkb kbkf kbkk kbkr kbra kbrb kbrc kbre kbrf kbrk kcaa kcab kcac kcar kcba kcbc kcbf kcbk kcbr kcca kccb kccc kcck kccr kcea kceb kcec kcee kcfa kcfb kcfc kckc kckf kckk kckr kcrc kcrr kea- keak kear keba kebb kebc kebe kebr keca keck kecr keef keek keer kefa kefb kefc keff kefr keka kekb kekc keke ker- kera kerb kerc kere kerf kerk kerr kfab kfac kfar kfbc kfbk kfcf kfcr kfeb kfer kffa kffb kfff kffk kfka kfkb kfra kfrc kfre kfrr kkaa kkac kkar kkba kkbb kkbe kkbr kkcb kkck kkcr kkea kkfr kkkk kkrb kkrc kkre kkrf kkrk kkrr krab krac krae krak krar krba krbb krbe krbk krbr krca krcb krcc krce krea kreb krec kree kref krek krfc krfe krff krka krkc krke