ddd ddn ddr dds ddt dnd dnn dnr dns dnt drd drn drr drs drt dsd dsn dsr dss dst dtd dtn dtr dts dtt ndd ndn ndr nds ndt nnn nns nnt nrd nrn nrr nrs nrt nsd nsn nsr nss nst ntd ntn ntr nts ntt rdd rdn rdr rds rdt rnd rnn rnr rns rnt rrd rrn rrr rrs rrt rsd rsn rsr rss rst rtd rtn rtr rts rtt sdd sdn sdr sds sdt snd snn snr sns snt sr- srd srn srr srs srt ss- ssd ssn ssr sss sst std stn str sts stt tdd tdn tdr tds tdt tnd tnn tnr tns tnt trd trn trr trs trt tsd tsn tsr tss tst ttd ttn ttr tts ttt