a-a a-b aaa aab aah aan aar ab- aba abb abh abn abr aha ahb ahh ahn ahr an- ana anb anh ann anr ar- ara arb arh arn arr baa bab bah ban bar bba bbb bbh bbn bbr bha bhb bhh bhr bna bnb bnn bnr bra brb brh brn brr haa hab hah han har hba hbb hbh hbn hbr hha hhb hhh hhn hhr hna hnb hnh hnn hr- hra hrb hrh hrn hrr naa nab nah nan nar nba nbb nbn nbr nha nhb nhh nhn nhr nna nnb nnh nnn nra nrb nrn nrr ra- raa rab rah ran rar rba rbb rbh rbn rbr rh- rha rhb rhh rhn rhr rna rnb rnh rnn rnr rra rrb rrh rrn rrr