-ey a-a a-b a-c aaa aab aac aae aaf aak aao aay ab- aba abb abc abe abf abk abo aby ac- aca acb acc ace acf ack aco acy aea aeb aec aee aef aek aeo aey af- afa afb afc afe aff afk afo afy aka akb akc ake akk ako aoa aob aoc aoe aof aok aoo ay- aya ayc aye ayf ayk ayo baa bab bac bae baf bak bao bay bba bbb bbc bbe bbf bbk bbo bby bca bcb bcc bce bcf bck bco bcy be- bea beb bec bee bef bek beo bey bfa bfb bfc bfe bff bfo bfy bka bkb bkc bke bkf bkk bko boa bob boc boe bof bok boo boy by- bya byc bye byf byk byo c-- caa cab cac cae caf cak cao cay cba cbb cbc cbe cbf cbk cbo cby cca ccb ccc cce ccf cck cco ce- cea ceb cec cee cef cek ceo cey cfa cfb cfc cfe cff cfk cfo cka ckb ckc cko cky co- coa cob coc coe cof cok coo coy cya cyb cyc cye cyf cyk cyo eaa eab eac eae eaf eak eao eba ebb ebc ebe ebf ebk ebo eby ec- eca ecb ecc ece ecf eck eco eea eeb eec eee eef eek eeo eey ef- efa efb efc efe eff efo eka ekb ekc eke ekf eko eky eo- eoa eob eoc eoe eof eok eoo eya eyc eye eyo faa fab fac fae faf fak fao fay fba fbb fbc fbe fbf fbk fbo fca fcb fcc fce fcf fck fco fcy fea feb fec fee fef fek feo fey ffa ffc ffe fff ffk ffo ffy fka fkb fkc fkf fkk foa fob foc foe fof fok foo foy fy- fya fyb fyc fye fyk fyo ka- kaa kab kac kae kaf kak kao kay kba kbb kbc kbe kbf kbk kbo kca kcb kcc kce kck ke- kea keb kec kee kef kek keo key kfa kfc kff kfo kkb kkc kke kkk kky koa kob koc koe kof kok koo koy kya kyc kye kyo oaa oab oac oae oaf oak oao ob- oba obb obc obe obf obk obo oby oc- oca ocb occ ocf ock oco oea oeb oec oee oef oeo oey of- ofa ofb ofc ofe off ofo oka okb okc oke okk oko oo- ooa oob ooc oof ook ooo oya oye oyo yaa yab yac yae yaf yak yao yay ybc ybe ybf yby yca ycc yce ycf yco ycy yea yeb yec yee yef yek yeo yey yfa yfc yfe yff yka ykk yob yoc yoe yof yok yoo yoy yyb yyc yye yyf yyy