a-a a-b a-c aaa aab aac aad aak aao aar aay ab- aba abb abc abd abk abo abr aby ac- aca acb acc acd ack aco acr acy ad- ada adb adc add adk ado adr ady aka akb akc akd akk ako akr aoa aob aoc aod aok aoo aor ar- ara arb arc ard ark aro arr ary ay- aya ayc ayd ayk ayo ayr baa bab bac bad bak bao bar bay bba bbb bbc bbd bbk bbo bbr bby bca bcb bcc bcd bck bco bcr bcy bda bdb bdc bdd bdk bdo bdr bdy bka bkb bkc bkk bko bkr boa bob boc bod bok boo bor boy bra brb brd brk bro brr bry by- bya byc byd byk byo byr c-- caa cab cac cad cak cao car cay cba cbb cbc cbd cbk cbo cbr cby cca ccb ccc ccd cck cco ccr cda cdb cdc cdd cdk cdo cdr cdy cka ckb ckc ckd cko cky co- coa cob coc cod cok coo cor coy cra crb crc crd crk cro crr cry cya cyb cyc cyd cyk cyo cyr daa dab dac dad dak dao dar day dba dbb dbc dbd dbk dbo dbr dby dca dcb dcc dcd dck dco dcr dda ddb ddc ddd ddk ddo ddr ddy dka dkb dkc dkk dko dkr doa dob doc dod dok doo dor doy dra drb drc drd drk dro drr dry dy- dya dyb dyc dyd dyk dyo dyr dyy ka- kaa kab kac kad kak kao kar kay kba kbb kbc kbd kbk kbo kbr kca kcb kcc kcd kck kcr kda kdb kdc kdk kdo kdr kdy kkb kkc kkk kkr kky koa kob koc kod kok koo kor koy kra krc krd krk kro krr kry kya kyc kyd kyo kyr oaa oab oac oad oak oao oar ob- oba obb obc obd obk obo obr oby oc- oca ocb occ ocd ock oco ocr oda odb odc odd odo odr oka okb okc okd okk oko okr oo- ooa oob ooc ood ook ooo oor or- ora orb orc ord ork oro orr ory oya oyd oyo ra- raa rab rac rad rak rao rar ray rba rbb rbc rbd rbk rbo rbr rca rcb rcc rcd rco rcr rda rdb rdc rdd rdo rdr rdy rkb rkc rkk rko rky roa rob roc rod rok roo ror roy rra rrb rrc rrd rrk rrr ry- rya ryc ryd ryk ryo ryr ryy yaa yab yac yad yak yao yar yay ybc ybr yby yca ycc ycd yco ycy yda ydo ydy yka ykk yob yoc yod yok yoo yor yoy yra yrc yro yyb yyc yyy