a-a a-b a-c aaa aab aac aah aau ab- aba abb abc abh abu ac- aca acb acc ach acu aha ahb ahc ahh ahu au- aua aub auc auh b-u baa bab bac bah bau bba bbb bbc bbh bbu bca bcb bcc bch bcu bha bhb bhc bhh bhu bua bub buc buh buu c-- caa cab cac cah cau cba cbb cbc cbh cbu cca ccb ccc cch ccu ch- cha chb chc chh chu cua cub cuc cuh cuu haa hab hac hah hau hba hbb hbc hbh hbu hca hcb hcc hch hha hhb hhc hhh hhu hua hub huc huh huu ua- uaa uab uac uah uau uba ubb ubc ubh ubu uca ucb ucc uch ucu uha uhb uhc uhh uhu uua uuc uuu