-th a-a a-b a-c a-t aaa aab aac aah aar aat ab- aba abb abc abh abr abt ac- aca acb acc ach acr act aha ahb ahc ahh ahr aht ar- ara arb arc arh arr art at- ata atb atc ath atr att baa bab bac bah bar bat bba bbb bbc bbh bbr bbt bca bcb bcc bch bcr bct bha bhb bhc bhh bhr bht bra brb brh brr brt bta btb btc bth btr btt c-- caa cab cac cah car cat cba cbb cbc cbh cbr cbt cca ccb ccc cch ccr cct ch- cha chb chc chh chr cht cra crb crc crh crr crt cta ctb ctc cth ctr ctt haa hab hac hah har hat hba hbb hbc hbh hbr hbt hca hcb hcc hch hcr hct hha hhb hhc hhh hhr hht hr- hra hrb hrc hrh hrr hrt hta htb htc hth htr htt ra- raa rab rac rah rar rat rba rbb rbc rbh rbr rbt rca rcb rcc rch rcr rct rh- rha rhb rhc rhh rhr rht rra rrb rrc rrh rrr rrt rta rtb rtc rtr rtt taa tab tac tah tar tat tba tbb tbc tbh tbr tbt tca tcb tcc tch tcr tct th- tha thb thc thh thr tht tra trb trc trh trr trt tta ttb ttc tth ttr ttt