a-a a-b a-c aaa aab aac aak aau aay ab- aba abb abc abk abu aby ac- aca acb acc ack acu acy aka akb akc akk aku au- aua aub auc auk ay- aya ayc ayk ayu b-u baa bab bac bak bau bay bba bbb bbc bbk bbu bby bca bcb bcc bck bcu bcy bka bkb bkc bkk bua bub buc buk buu buy by- bya byc byk byu c-- caa cab cac cak cau cay cba cbb cbc cbk cbu cby cca ccb ccc cck ccu cka ckb ckc cky cua cub cuc cuk cuu cuy cya cyb cyc cyk ka- kaa kab kac kak kau kay kba kbb kbc kbk kbu kca kcb kcc kck kcu kkb kkc kkk kku kky kub kuc kuk kuu kuy kya kyc kyu ua- uaa uab uac uak uau uay uba ubb ubc ubk ubu uby uca ucb ucc uck ucu uka ukb ukc ukk uku uua uuc uuu uyc uyu yaa yab yac yak yau yay ybc yby yca ycc ycu ycy yka ykk yua yuk yuu yuy yyb yyc yyu yyy