a-a a-b aaa aab aaf aar aau aay ab- aba abb abf abr abu aby af- afa afb aff afr afu afy ar- ara arb arf arr aru ary au- aua aub auf aur ay- aya ayf ayr ayu b-u baa bab baf bar bau bay bba bbb bbf bbr bbu bby bfa bfb bff bfr bfu bfy bra brb brf brr bru bry bua bub buf bur buu buy by- bya byf byr byu faa fab faf far fau fay fba fbb fbf fbr fbu ffa fff ffr ffu ffy fra frb frf frr fru fry fua fub fuf fur fuu fy- fya fyb ra- raa rab raf rar rau ray rba rbb rbf rbr rbu rfa rfb rff rfr rfu rra rrb rrf rrr rru rua rub ruf rur ruu ruy ry- rya ryf ryr ryu ryy ua- uaa uab uaf uar uau uay uba ubb ubf ubr ubu uby ufa uff ufr ufu ur- ura urb urf urr uru ury uua uur uuu uyu yaa yab yaf yar yau yay ybf ybr yby yfa yff yfr yfu yra yrf yru yua yur yuu yuy yyb yyf yyu yyy