a-a a-b aaa aab aam aau aax ab- aba abb abm abu abx ama amb amm amu amx au- aua aub aum aux ax- axa axm axx b-u baa bab bam bau bax bba bbb bbm bbu bbx bma bmb bmm bmu bmx bua bub bum buu bux bxb bxm bxx maa mab mam mau max mba mbb mbm mbu mbx mma mmb mmm mmu mmx mua mub mum muu mux mxa mxu ua- uaa uab uam uau uba ubb ubu ubx um- uma umb umm umu uua uum uuu uxb uxu xaa xam xau xbx xma xmm xmu xmx xxx