a-a a-b a-c aaa aab aac aah aak aay ab- aba abb abc abh abk aby ac- aca acb acc ach ack acy aha ahb ahc ahh ahk ahy aka akb akc akh akk ay- aya ayc ayh ayk baa bab bac bah bak bay bba bbb bbc bbh bbk bby bca bcb bcc bch bck bcy bha bhb bhc bhh bhk bka bkb bkc bkk by- bya byc byh byk c-- caa cab cac cah cak cay cba cbb cbc cbh cbk cby cca ccb ccc cch cck ch- cha chb chc chh chk chy cka ckb ckc ckh cky cya cyb cyc cyk haa hab hac hah hak hay hba hbb hbc hbh hbk hby hca hcb hcc hch hck hcy hha hhb hhc hhh hhk hhy hka hkb hkh hkk hy- hya hyb hyc hyh hyy ka- kaa kab kac kah kak kay kba kbb kbc kbh kbk kca kcb kcc kch kck kha khh khk kkb kkc kkh kkk kky kya kyc yaa yab yac yah yak yay ybc yby yca ycc ych ycy yha yhc yka ykk yyb yyc yyy