a-a a-b a-c a-t aaa aab aac aad aar aas aat ab- aba abb abc abd abr abs abt ac- aca acb acc acd acr acs act ad- ada adb adc add adr ads adt ar- ara arb arc ard arr ars art as- asa asb asc asd asr ass ast at- ata atb atc atd atr ats att baa bab bac bad bar bas bat bba bbb bbc bbd bbr bbs bbt bca bcb bcc bcd bcr bcs bct bda bdb bdc bdd bdr bds bdt bra brb brd brr brs brt bsa bsb bsc bsd bsr bss bst bta btb btc btd btr bts btt c-- caa cab cac cad car cas cat cba cbb cbc cbd cbr cbs cbt cca ccb ccc ccd ccr ccs cct cda cdb cdc cdd cdr cds cdt cra crb crc crd crr crs crt csa csb csc csd csr css cst cta ctb ctc ctd ctr cts ctt daa dab dac dad dar das dat dba dbb dbc dbd dbr dbs dbt dca dcb dcc dcd dcr dcs dct dda ddb ddc ddd ddr dds ddt dra drb drc drd drr drs drt dsa dsb dsc dsd dsr dss dst dta dtb dtc dtd dtr dts dtt ra- raa rab rac rad rar ras rat rba rbb rbc rbd rbr rbs rbt rca rcb rcc rcd rcr rcs rct rda rdb rdc rdd rdr rds rdt rra rrb rrc rrd rrr rrs rrt rsa rsb rsc rsd rsr rss rst rta rtb rtc rtd rtr rts rtt saa sab sac sad sar sas sat sba sbb sbc sbd sbr sbs sbt sca scb scc scd scr scs sct sda sdb sdc sdd sdr sds sdt sr- sra srb src srd srr srs srt ss- ssa ssb ssc ssd ssr sss sst sta stb stc std str sts stt taa tab tac tad tar tas tat tba tbb tbc tbd tbr tbs tbt tca tcb tcc tcd tcr tcs tct tda tdb tdc tdd tdr tds tdt tra trb trc trd trr trs trt tsa tsb tsc tsd tsr tss tst tta ttb ttc ttd ttr tts ttt