a-a a-b a-c aaa aab aac aak aas aau aay ab- aba abb abc abk abs abu aby ac- aca acb acc ack acs acu acy aka akb akc akk aks aku as- asa asb asc ask ass asu asy au- aua aub auc auk aus ay- aya ayc ayk ays ayu b-u baa bab bac bak bas bau bay bba bbb bbc bbk bbs bbu bby bca bcb bcc bck bcs bcu bcy bka bkb bkc bkk bks bsa bsb bsc bsk bss bsu bsy bua bub buc buk bus buu buy by- bya byc byk bys byu c-- caa cab cac cak cas cau cay cba cbb cbc cbk cbs cbu cby cca ccb ccc cck ccs ccu cka ckb ckc cks cky csa csb csc csk css csu csy cua cub cuc cuk cus cuu cuy cya cyb cyc cyk cys ka- kaa kab kac kak kas kau kay kba kbb kbc kbk kbs kbu kca kcb kcc kck kcs kcu kkb kkc kkk kks kku kky ksa ksb ksc ksk kss ksu kub kuc kuk kus kuu kuy kya kyc kys kyu saa sab sac sak sas sau say sba sbb sbc sbk sbs sbu sby sca scb scc sck scs scu sk- ska skb skc skk sks sku sky ss- ssa ssb ssc ssk sss ssu sua sub suc suk sus suu suy sy- sya syb syc syk sys syu ua- uaa uab uac uak uas uau uay uba ubb ubc ubk ubs ubu uby uca ucb ucc uck ucs ucu uka ukb ukc ukk uku usa usb usc usk uss usu uua uuc uus uuu uyc uys uyu yaa yab yac yak yas yau yay ybc ybs yby yca ycc ycs ycu ycy yka ykk ysa ysb ysc ysk yss ysu ysy yua yuk yus yuu yuy yyb yyc yys yyu yyy