a-a a-b a-c aaa aab aac aak aao aau aay ab- aba abb abc abk abo abu aby ac- aca acb acc ack aco acu acy aka akb akc akk ako aku aoa aob aoc aok aoo aou au- aua aub auc auk auo ay- aya ayc ayk ayo ayu b-u baa bab bac bak bao bau bay bba bbb bbc bbk bbo bbu bby bca bcb bcc bck bco bcu bcy bka bkb bkc bkk bko boa bob boc bok boo bou boy bua bub buc buk buo buu buy by- bya byc byk byo byu c-- caa cab cac cak cao cau cay cba cbb cbc cbk cbo cbu cby cca ccb ccc cck cco ccu cka ckb ckc cko cky co- coa cob coc cok coo cou coy cua cub cuc cuk cuo cuu cuy cya cyb cyc cyk cyo ka- kaa kab kac kak kao kau kay kba kbb kbc kbk kbo kbu kca kcb kcc kck kcu kkb kkc kkk kku kky koa kob koc kok koo kou koy kub kuc kuk kuu kuy kya kyc kyo kyu oaa oab oac oak oao oau ob- oba obb obc obk obo obu oby oc- oca ocb occ ock oco ocu oka okb okc okk oko oku oo- ooa oob ooc ook ooo ou- oua ouc ouk ouo oya oyo ua- uaa uab uac uak uao uau uay uba ubb ubc ubk ubo ubu uby uca ucb ucc uck uco ucu uka ukb ukc ukk uku uoa uob uoc uok uoo uua uuc uuu uyc uyo uyu yaa yab yac yak yao yau yay ybc yby yca ycc yco ycu ycy yka ykk yob yoc yok yoo you yoy yua yuk yuo yuu yuy yyb yyc yyu yyy