a-a a-b a-c aaa aab aac aar aau aay ab- aba abb abc abr abu aby ac- aca acb acc acr acu acy ar- ara arb arc arr aru ary au- aua aub auc aur ay- aya ayc ayr ayu b-u baa bab bac bar bau bay bba bbb bbc bbr bbu bby bca bcb bcc bcr bcu bcy bra brb brr bru bry bua bub buc bur buu buy by- bya byc byr byu c-- caa cab cac car cau cay cba cbb cbc cbr cbu cby cca ccb ccc ccr ccu cra crb crc crr cru cry cua cub cuc cur cuu cuy cya cyb cyc cyr ra- raa rab rac rar rau ray rba rbb rbc rbr rbu rca rcb rcc rcr rcu rra rrb rrc rrr rru rua rub ruc rur ruu ruy ry- rya ryc ryr ryu ryy ua- uaa uab uac uar uau uay uba ubb ubc ubr ubu uby uca ucb ucc ucr ucu ur- ura urb urc urr uru ury uua uuc uur uuu uyc uyu yaa yab yac yar yau yay ybc ybr yby yca ycc ycu ycy yra yrc yru yua yur yuu yuy yyb yyc yyu yyy