a-a aaa aaf aam aax aay af- afa aff afm afx afy ama amf amm amx amy ax- axa axm axx ay- aya ayf ayx faa faf fam fax fay ffa fff ffm ffx ffy fma fmf fmm fmx fxm fxx fy- fya m-f maa maf mam max may mfa mff mfm mfy mma mmf mmm mmx mxa my- mya myf mym myx xaa xaf xam xfa xfm xfx xma xmf xmm xmx xxx xxy xyy yaa yaf yam yax yay yfa yff yfm yma ymm yxa yxy yyf yyy