d-ix dddd dfdt didi didy dif- diff dify diii diti ditt dixi dixy diyi dttx dtxt dxfx dxif dxii dxix dxty dxxx dydd dyf- dyfi dyfx dyit dyt- dytx dyty dyxx dyxy fdti ffff ffii fftf fidf fiff fifi fift fiii fiti fitt fixt fixx fixy ftdi ftfy ftii fxdd fyfi fyti idid iffy ifid ifit iiii iiit iitt itif ittf itty ixxi tdff tidd tidy tiff tift tiit titi titt tixt tiyi ttff tttt ttyd txii tydd tydi tydy tyff tyft tytd tyti tytt tyty tyxt x-fi xdxf xidi xify xiii xixi xxii xxix xxxi xxxx xxxy ydyt yidi yiff yift yiti yyff yyyy