a-a a-z aaa aad aaf aar aaz ad- ada add adf adr adz af- afa afd aff afr afz ar- ara ard arf arr arz az- aza azd azf azz daa dad daf dar daz dda ddd ddf ddr ddz dfa dfd dff dfr dfz dra drd drr drz dza dzd dzr faa fad faf far faz fda fdd fdf fdr ffa ffd fff ffr ffz fra frd frf frr fzd ra- raa rad raf rar raz rda rdd rdf rdr rfa rfd rff rfr rfz rra rrd rrf rrr rza zaa zad zaf zar zaz zdf zfa zfd zfr zzr zzz