-ey a-a a-b a-c aaa aab aac aae aaf aak aay ab- aba abb abc abe abf abk aby ac- aca acb acc ace acf ack acy aea aeb aec aee aef aek aey af- afa afb afc afe aff afk afy aka akb akc ake akk ay- aya ayc aye ayf ayk baa bab bac bae baf bak bay bba bbb bbc bbe bbf bbk bby bca bcb bcc bce bcf bck bcy be- bea beb bec bee bef bek bey bfa bfb bfc bfe bff bfy bka bkb bkc bke bkf bkk by- bya byc bye byf byk c-- caa cab cac cae caf cak cay cba cbb cbc cbe cbf cbk cby cca ccb ccc cce ccf cck ce- cea ceb cec cee cef cek cey cfa cfb cfc cfe cff cfk cka ckb ckc cky cya cyb cyc cye cyf cyk eaa eab eac eae eaf eak eba ebb ebc ebe ebf ebk eby ec- eca ecb ecc ece ecf eck eea eeb eec eee eef eek eey ef- efa efb efc efe eff eka ekb ekc eke ekf eky eya eyc eye faa fab fac fae faf fak fay fba fbb fbc fbe fbf fbk fca fcb fcc fce fcf fck fcy fea feb fec fee fef fek fey ffa ffc ffe fff ffk ffy fka fkb fkc fkf fkk fy- fya fyb fyc fye fyk ka- kaa kab kac kae kaf kak kay kba kbb kbc kbe kbf kbk kca kcb kcc kce kck ke- kea keb kec kee kef kek key kfa kfc kff kkb kkc kke kkk kky kya kyc kye yaa yab yac yae yaf yak yay ybc ybe ybf yby yca ycc yce ycf ycy yea yeb yec yee yef yek yey yfa yfc yfe yff yka ykk yyb yyc yye yyf yyy