-th a-a a-b a-c a-t aaa aab aac aah aat ab- aba abb abc abh abt ac- aca acb acc ach act aha ahb ahc ahh aht at- ata atb atc ath att baa bab bac bah bat bba bbb bbc bbh bbt bca bcb bcc bch bct bha bhb bhc bhh bht bta btb btc bth btt c-- caa cab cac cah cat cba cbb cbc cbh cbt cca ccb ccc cch cct ch- cha chb chc chh cht cta ctb ctc cth ctt haa hab hac hah hat hba hbb hbc hbh hbt hca hcb hcc hch hct hha hhb hhc hhh hht hta htb htc hth htt taa tab tac tah tat tba tbb tbc tbh tbt tca tcb tcc tch tct th- tha thb thc thh tht tta ttb ttc tth ttt