a-a aaa aad aan aar aax ad- ada add adn adr adx an- ana and ann anr anx ar- ara ard arn arr arx ax- axa axn axr axx daa dad dan dar dax dda ddd ddn ddr ddx dna dnd dnn dnr dra drd drn drr drx dxd dxn dxr dxx naa nad nan nar nax nda ndd ndn ndr nna nnn nra nrd nrn nrr nrx nxd ra- raa rad ran rar rax rda rdd rdn rdr rdx rna rnd rnn rnr rra rrd rrn rrr rxr xaa xad xan xar xda xdr xna xrd xrx xxx