-er a-a a-b a-c aaa aab aac aae aak aao aar aax ab- aba abb abc abe abk abo abr abx ac- aca acb acc ace ack aco acr acx aea aeb aec aee aek aeo aer aex aka akb akc ake akk ako akr aoa aob aoc aoe aok aoo aor aox ar- ara arb arc are ark aro arr arx ax- axa axe axk axo axr axx baa bab bac bae bak bao bar bax bba bbb bbc bbe bbk bbo bbr bbx bca bcb bcc bce bck bco bcr bcx be- bea beb bec bee bek beo ber bex bka bkb bkc bke bkk bko bkr bkx boa bob boc boe bok boo bor box bra brb bre brk bro brr brx bxb bxo bxx c-- caa cab cac cae cak cao car cax cba cbb cbc cbe cbk cbo cbr cbx cca ccb ccc cce cck cco ccr ccx ce- cea ceb cec cee cek ceo cer cex cka ckb ckc cko ckx co- coa cob coc coe cok coo cor cox cra crb crc cre crk cro crr crx cxc cxk cxo cxr cxx eaa eab eac eae eak eao ear eax eba ebb ebc ebe ebk ebo ebr ebx ec- eca ecb ecc ece eck eco ecr ecx eea eeb eec eee eek eeo eer eex eka ekb ekc eke eko ekr eo- eoa eob eoc eoe eok eoo eor era erb erc ere erk ero err ex- exa exc exe exo exr exx ka- kaa kab kac kae kak kao kar kax kba kbb kbc kbe kbk kbo kbr kbx kca kcb kcc kce kck kcr kcx ke- kea keb kec kee kek keo ker kex kkb kkc kke kkk kkr koa kob koc koe kok koo kor kra krc krk kro krr kxo oaa oab oac oae oak oao oar oax ob- oba obb obc obe obk obo obr obx oc- oca ocb occ ock oco ocr ocx oea oeb oec oee oeo oer oex oka okb okc oke okk oko okr oo- ooa oob ooc ook ooo oor oox or- ora orb orc ore ork oro orr orx ox- oxa oxb oxc oxo oxx ra- raa rab rac rae rak rao rar rax rba rbb rbc rbe rbk rbo rbr rbx rca rcb rcc rce rco rcr rcx re- rea reb rec ree rek reo rer rex rkb rkc rke rkk rko roa rob roc roe rok roo ror rox rra rrb rrc rrk rrr rxr xaa xac xak xar xbc xbe xbr xbx xcb xcr xcx xee xer xex xkb xke xoa xoc xok xoo xor xox xrc xrx xxo xxx

a-ak a-be a-ok aaaa aaab aaac aaae aaar aaba aabb aabc aaca aacb aacc aace aack aaco aacr aaea aaec aaka aake aaoe aaoo aara aarc aare aaro abaa abab abac abae abak abar abax abb- abba abbb abbe abbo abbr abca abcb abcc abcr abec abee aber aboa abob abok aboo abor abox abra abrc abro acaa acab acac acae acar acba acca accc acce acco ace- acea acec acek acer acke acoa acoe acor acr- acra acrc acre acro acrr aeac aecb aeer aeka aer- aera aerc aero akaa akae akao akar akca akee aker akka akko akok akr- akra akre aoba aoca aoce aora aorb arab arac arae arak arar arax arba arbe arc- arca arce arco area arec aree arek areo arex arka arke arko aroa arob aroe aroo aror arr- arra arrc arre arrk arro arrr axar axce axer axo- axoa axxo ba-x baaa baak baar baba babb babe babo babr bac- baca bacc bace back baco baek baer bak- baka bake bako bakr bar- bara barb barc bare bark baro barr barx bbbb bbeb bbox bbrc bcaa bcar bcbc bcca bccc bcec bcer bcor bcra beak bear beba bebb bebe bebo beca beck beeb beek beer beka beke beko beo- beok beor bera berc bere berk bero berr boab boac boak boar boba bobb bobe bobo boca boce bock boco boea boec boee boeo boer boka boke boko boob booc booe book boor boox bor- bora bore bork boro borr boxa brab brac brae brak brao brax brca brcb brce brea breb brec bree brek breo brer brex brka brkb broa brob broc broe brok broo bror brox brrr c-bo caaa caab caac caba cabe cabo cac- caca cacc cace cack caco cacr caec caer caex caka cake caor cara carb carc care cark caro carr carx caxa cbac cbar cbax cbbc cbca cbcc cbce cbcr cbea cbec cbee cber cbka cbko cbkr cbox cbre cbxa ccaa ccab ccac ccar ccba ccbc ccca cccb cccc ccee ccob ccoc ccra ccrc ccre ceac cear ceba cec- ceca cece ceco ceeb ceec ceke ceor cer- cera cerc cere cero cexe ckac ckbc ckbe ckbx ckck ckco ckcx cker ckoa ckob ckoc ckoo ckor ckrc coak coax coba cobb cobe cobo coca coce cock coco coex cok- coka coke coko coob cook cor- cora corb corc core cork coro corr coxa coxe crab crac crar crax crbc crca crcc crce crcr cre- crea creb crec cree creo crex crkc crob croc croe crok croo cror cxro cxxx eaba eaca eacc eaec eara earb eare earo ebac ebba ebbc ebbo ebbr ebcc eber eboe eboo ebor ebox ebro ecaa ecac ecao ecar ecbc ecbe ecca eccb eccc ecce ecco ecka ecko eco- ecra ecrc ecrr eeca eeea eeee eeka eeke eeoc eera eerc eero eka- ekab ekco ekeb ekek eker ekka ekoa eoka eora eore er-x erba erbb erbe erca ercc erce ereb erec erer erke erob eroc eroe eroo erra errc erre erro exa- exco exec exer exo- exor exrx kaaa kaab kaak kaar kaba kabb kabc kabe kabo kabr kacb kacc kace kaco kaeo kaer kaka kakc kake kakk kako kakx kaoa kaoc kaok kaor kaox kara karb kare kark karo karr karx kaxa kaxe kbaa kbab kbac kbae kbak kbar kbba kbbb kbbc kbbe kbbk kbbo kbbr kbca kbcb kbce kbck kbco kbcr kbeb