-ey a-a a-b a-c aaa aab aac aae aao aas aay ab- aba abb abc abe abo abs aby ac- aca acb acc ace aco acs acy aea aeb aec aee aeo aes aey aoa aob aoc aoe aoo aos as- asa asb asc ase aso ass asy ay- aya ayc aye ayo ays baa bab bac bae bao bas bay bba bbb bbc bbe bbo bbs bby bca bcb bcc bce bco bcs bcy be- bea beb bec bee beo bes bey boa bob boc boe boo bos boy bsa bsb bsc bse bso bss bsy by- bya byc bye byo bys c-- caa cab cac cae cao cas cay cba cbb cbc cbe cbo cbs cby cca ccb ccc cce cco ccs ce- cea ceb cec cee ceo ces cey co- coa cob coc coe coo cos coy csa csb csc cse cso css csy cya cyb cyc cye cyo cys eaa eab eac eae eao eas eba ebb ebc ebe ebo ebs eby ec- eca ecb ecc ece eco ecs eea eeb eec eee eeo ees eey eo- eoa eob eoc eoe eoo eos es- esa esb esc ese eso ess esy eya eyc eye eyo eys oaa oab oac oae oao oas ob- oba obb obc obe obo obs oby oc- oca ocb occ oco ocs oea oeb oec oee oeo oes oey oo- ooa oob ooc ooo oos os- osa osb osc ose oso oss oya oye oyo oys saa sab sac sae sao sas say sba sbb sbc sbe sbo sbs sby sca scb scc sce sco scs se- sea seb sec see seo ses sey soa sob soc soe soo sos soy ss- ssa ssb ssc sse sso sss sy- sya syb syc sye sys yaa yab yac yae yao yas yay ybc ybe ybs yby yca ycc yce yco ycs ycy yea yeb yec yee yeo yes yey yob yoc yoe yoo yos yoy ysa ysb ysc yse yso yss ysy yyb yyc yye yys yyy