a-a a-b aaa aab aah aar aas ab- aba abb abh abr abs aha ahb ahh ahr ahs ar- ara arb arh arr ars as- asa asb ash asr ass baa bab bah bar bas bba bbb bbh bbr bbs bha bhb bhh bhr bhs bra brb brh brr brs bsa bsb bsh bsr bss haa hab hah har has hba hbb hbh hbr hbs hha hhb hhh hhr hhs hr- hra hrb hrh hrr hrs hsa hsb hsh hsr hss ra- raa rab rah rar ras rba rbb rbh rbr rbs rh- rha rhb rhh rhr rhs rra rrb rrh rrr rrs rsa rsb rsh rsr rss saa sab sah sar sas sba sbb sbh sbr sbs sh- sha shb shh shr shs sr- sra srb srh srr srs ss- ssa ssb ssh ssr sss