-ey a-a a-b a-c aaa aab aac aae aay ab- aba abb abc abe aby ac- aca acb acc ace acy aea aeb aec aee aey ay- aya ayc aye baa bab bac bae bay bba bbb bbc bbe bby bca bcb bcc bce bcy be- bea beb bec bee bey by- bya byc bye c-- caa cab cac cae cay cba cbb cbc cbe cby cca ccb ccc cce ce- cea ceb cec cee cey cya cyb cyc cye eaa eab eac eae eba ebb ebc ebe eby ec- eca ecb ecc ece eea eeb eec eee eey eya eyc eye yaa yab yac yae yay ybc ybe yby yca ycc yce ycy yea yeb yec yee yey yyb yyc yye yyy