a-a a-c a-t aaa aac aan aar aat ac- aca acc acn acr act an- ana anc ann anr ant ar- ara arc arn arr art at- ata atc atn atr att c-- caa cac can car cat cca ccc ccn ccr cct cn- cna cnc cnn cnr cnt cra crc crn crr crt cta ctc ctn ctr ctt naa nac nan nar nat nca ncc ncn ncr nct nna nnc nnn nnt nra nrc nrn nrr nrt nta ntc ntn ntr ntt ra- raa rac ran rar rat rca rcc rcn rcr rct rna rnc rnn rnr rnt rra rrc rrn rrr rrt rta rtc rtn rtr rtt taa tac tan tar tat tca tcc tcn tcr tct tna tnc tnn tnr tnt tra trc trn trr trt tta ttc ttn ttr ttt