a-a a-t aaa aan aar aat aax an- ana ann anr ant anx ar- ara arn arr art arx at- ata atn atr att atx ax- axa axn axr axt axx naa nan nar nat nax nna nnn nnt nra nrn nrr nrt nrx nta ntn ntr ntt ntx nxt ra- raa ran rar rat rax rna rnn rnr rnt rra rrn rrr rrt rta rtn rtr rtt rtx rxr t-x taa tan tar tat tax tna tnn tnr tnt tnx tra trn trr trt trx tta ttn ttr ttt ttx txn txt xaa xan xar xat xna xrt xrx xtr xtx xxx