a-a a-b aaa aab aak aar aau ab- aba abb abk abr abu aka akb akk akr aku ar- ara arb ark arr aru au- aua aub auk aur b-u baa bab bak bar bau bba bbb bbk bbr bbu bka bkb bkk bkr bra brb brk brr bru bua bub buk bur buu ka- kaa kab kak kar kau kba kbb kbk kbr kbu kkb kkk kkr kku kra krk krr kru kub kuk kur kuu ra- raa rab rak rar rau rba rbb rbk rbr rbu rkb rkk rku rra rrb rrk rrr rru rua rub ruk rur ruu ua- uaa uab uak uar uau uba ubb ubk ubr ubu uka ukb ukk ukr uku ur- ura urb urk urr uru uua uur uuu