a-a a-b a-c aaa aab aac aah aar ab- aba abb abc abh abr ac- aca acb acc ach acr aha ahb ahc ahh ahr ar- ara arb arc arh arr baa bab bac bah bar bba bbb bbc bbh bbr bca bcb bcc bch bcr bha bhb bhc bhh bhr bra brb brh brr c-- caa cab cac cah car cba cbb cbc cbh cbr cca ccb ccc cch ccr ch- cha chb chc chh chr cra crb crc crh crr haa hab hac hah har hba hbb hbc hbh hbr hca hcb hcc hch hcr hha hhb hhc hhh hhr hr- hra hrb hrc hrh hrr ra- raa rab rac rah rar rba rbb rbc rbh rbr rca rcb rcc rch rcr rh- rha rhb rhc rhh rhr rra rrb rrc rrh rrr