a-a a-b a-c aaa aab aac aak aao aap aar aas ab- aba abb abc abk abo abp abr abs ac- aca acb acc ack aco acp acr acs aka akb akc akk ako akp akr aks aoa aob aoc aok aoo aop aor aos ap- apa apb apc apk apo app apr aps ar- ara arb arc ark aro arp arr ars as- asa asb asc ask aso asp asr ass b-p baa bab bac bak bao bap bar bas bba bbb bbc bbk bbo bbp bbr bbs bca bcb bcc bck bco bcp bcr bcs bka bkb bkc bkk bko bkp bkr bks boa bob boc bok boo bop bor bos bpa bpb bpc bpo bpp bpr bps bra brb brk bro brp brr brs bsa bsb bsc bsk bso bsp bsr bss c-- caa cab cac cak cao cap car cas cba cbb cbc cbk cbo cbp cbr cbs cca ccb ccc cck cco ccp ccr ccs cka ckb ckc cko cks co- coa cob coc cok coo cop cor cos cpa cpb cpc cpk cpo cpp cpr cps cra crb crc crk cro crp crr crs csa csb csc csk cso csp csr css ka- kaa kab kac kak kao kap kar kas kba kbb kbc kbk kbo kbp kbr kbs kca kcb kcc kck kcp kcr kcs kkb kkc kkk kkp kkr kks koa kob koc kok koo kop kor kos kpa kpc kpk kpo kpp kpr kps kra krc krk kro krp krr krs ksa ksb ksc ksk kso ksp ksr kss oaa oab oac oak oao oap oar oas ob- oba obb obc obk obo obp obr obs oc- oca ocb occ ock oco ocp ocr ocs oka okb okc okk oko okp okr oks oo- ooa oob ooc ook ooo oop oor oos op- opa opb opc opk opo opp opr ops or- ora orb orc ork oro orp orr ors os- osa osb osc osk oso osp osr oss p-p paa pab pac pak pao pap par pas pba pbb pbc pbk pbo pbp pbr pbs pca pcb pcc pck pco pcp pcr pcs pka pkb pkc pko pkp pkr pks poa pob poc pok poo pop por pos ppa ppb ppc ppk ppo ppp ppr pps pra prb prc prk pro prp prr prs ps- psa psb psc psk pso psp psr pss ra- raa rab rac rak rao rap rar ras rba rbb rbc rbk rbo rbp rbr rbs rca rcb rcc rco rcp rcr rcs rkb rkc rkk rko rkp rks roa rob roc rok roo rop ror ros rpa rpb rpc rpk rpo rpp rpr rps rra rrb rrc rrk rrp rrr rrs rsa rsb rsc rsk rso rsp rsr rss saa sab sac sak sao sap sar sas sba sbb sbc sbk sbo sbp sbr sbs sca scb scc sck sco scp scr scs sk- ska skb skc skk sko skp skr sks soa sob soc sok soo sop sor sos spa spb spc spk spo spp spr sps sr- sra srb src srk sro srp srr srs ss- ssa ssb ssc ssk sso ssp ssr sss

a-ak a-ok aaaa aaab aaac aaap aaar aaas aaba aabb aabc aabp aaca aacb aacc aack aaco aacp aacr aacs aaka aaoo aapa aapc aapo aaps aara aarc aaro aarp aars aasa aasc aass abaa abab abac abak abap abar abas abb- abba abbb abbo abbr abbs abca abcb abcc abcp abcr abcs aboa abob abok aboo abor abos abpa abpc abpp abpr abps abra abrc abro abrs abs- absa absp abss acaa acab acac acap acar acas acba acca accc acco accp accs acks acoa acop acor acos acpa acpr acps acr- acra acrc acro acrr acrs acsa acsc acss akaa akao akap akar akas akca akka akko akok akos akpo akr- akra aksa aoba aoca aocs aokp aoks aopo aora aorb aors aosp aoss apac apak apao apap apar apas apba apbr apbs apca apcb apcc apco apcr apcs apo- apoc apoo apop apor apos appa appc appr apps apra aprc apro aprs apsa apso apss arab arac arak arap arar aras arba arbs arc- arca arco arcs arka arko arks aroa arob aroo aror aros arpa arps arr- arra arrc arrk arro arrr arrs ars- arsa arsc arsk arso asaa asab asac asak asao asap asar asas asba asbo asc- asca ascb ascc asco ascp ascr aska asko askr asks asob asoc asok asop asor asos aspa aspc aspo aspr asps asra asrc asro asrs assa assc assk asso assp assr asss baaa baak baar baas baba babb babo babr babs bac- baca bacc back baco bacs bak- baka bako bakr baks baos bapa bapc bapp baps bar- bara barb barc bark baro barr bars basa basc bask baso bass bbas bbbb bbbs bbpr bbrc bcaa bcap bcar bcas bcbc bcbp bcbs bcca bccc bccs bcor bcos bcpp bcps bcra bcrs bcsa bcsc bcss bkpr bksp boab boac boak boar boas boba bobb bobo bobs boca bock boco bocs boka boko boks boob booc book boop boor boos bopa bopp bops bor- bora bork boro borr bors bosa bosc bosk boso boss bpcp bprc bpsa brab brac brak brao bras brca brcb brka brkb broa brob broc brok broo bror bros brrr brrs brsb brsr bsaa bsac bsap bsas bscp bscs bsos bspp bspr bsra bssc c-bo caaa caab caac caap caas caba cabo cabs cac- caca cacc cack caco cacr caka caor caos capa capb capc capo capp caps cara carb carc cark caro carp carr cars casa casb casc cask caso casp casr cass cbac cbar cbbc cbbs cbca cbcc cbcp cbcr cbcs cbka cbko cbkr cbpc cbpp cbsa cbsc ccaa ccab ccac ccap ccar ccas ccba ccbc ccca cccb cccc cccp cccs ccob ccoc ccpa ccpp ccpr ccps ccra ccrc ccrp ccrs ccsa ccsp ccss ckac ckbc ckck ckco ckcs ckoa ckob ckoc ckoo ckor ckos ckpc ckpr ckrc cksa cksb ckso coak coas coba cobb cobo cobs coca cock coco cocp cok-