a-a a-b a-c a-t aaa aab aac aad aaf aak aar aas aat ab- aba abb abc abd abf abk abr abs abt ac- aca acb acc acd acf ack acr acs act ad- ada adb adc add adf adk adr ads adt af- afa afb afc afd aff afk afr afs aft aka akb akc akd akk akr aks ar- ara arb arc ard arf ark arr ars art as- asa asb asc asd asf ask asr ass ast at- ata atb atc atd atf atr ats att baa bab bac bad baf bak bar bas bat bba bbb bbc bbd bbf bbk bbr bbs bbt bca bcb bcc bcd bcf bck bcr bcs bct bda bdb bdc bdd bdf bdk bdr bds bdt bfa bfb bfc bfd bff bfr bfs bft bka bkb bkc bkf bkk bkr bks bkt bra brb brd brf brk brr brs brt bsa bsb bsc bsd bsf bsk bsr bss bst bta btb btc btd btf btk btr bts btt c-- caa cab cac cad caf cak car cas cat cba cbb cbc cbd cbf cbk cbr cbs cbt cca ccb ccc ccd ccf cck ccr ccs cct cda cdb cdc cdd cdf cdk cdr cds cdt cfa cfb cfc cfd cff cfk cfr cfs cft cka ckb ckc ckd cks ckt cra crb crc crd crf crk crr crs crt csa csb csc csd csf csk csr css cst cta ctb ctc ctd ctf ctk ctr cts ctt daa dab dac dad daf dak dar das dat dba dbb dbc dbd dbf dbk dbr dbs dbt dca dcb dcc dcd dcf dck dcr dcs dct dda ddb ddc ddd ddf ddk ddr dds ddt dfa dfb dfc dfd dff dfk dfr dfs dft dka dkb dkc dkk dkr dks dkt dra drb drc drd drk drr drs drt dsa dsb dsc dsd dsf dsk dsr dss dst dta dtb dtc dtd dtf dtk dtr dts dtt faa fab fac fad faf fak far fas fat fba fbb fbc fbd fbf fbk fbr fbs fbt fca fcb fcc fcd fcf fck fcr fcs fct fda fdb fdc fdd fdf fdk fdr fds fdt ffa ffc ffd fff ffk ffr ffs fft fka fkb fkc fkf fkk fkt fra frb frc frd frf frk frr frs frt fsa fsb fsc fsd fsf fsk fsr fss fst fta ftb ftc ftd ftf ftk ftr fts ftt k-t ka- kaa kab kac kad kaf kak kar kas kat kba kbb kbc kbd kbf kbk kbr kbs kca kcb kcc kcd kck kcr kcs kct kda kdb kdc kdf kdk kdr kds kdt kfa kfc kfd kff kfs kkb kkc kkk kkr kks kkt kra krc krd krf krk krr krs krt ksa ksb ksc ksd ksf ksk ksr kss kst kta ktb ktc ktf ktk ktr kts ktt ra- raa rab rac rad raf rak rar ras rat rba rbb rbc rbd rbf rbk rbr rbs rbt rca rcb rcc rcd rcf rcr rcs rct rda rdb rdc rdd rdf rdr rds rdt rfa rfb rfc rfd rff rfk rfr rfs rft rkb rkc rkf rkk rks rkt rra rrb rrc rrd rrf rrk rrr rrs rrt rsa rsb rsc rsd rsf rsk rsr rss rst rta rtb rtc rtd rtf rtk rtr rts rtt saa sab sac sad saf sak sar sas sat sba sbb sbc sbd sbf sbk sbr sbs sbt sca scb scc scd scf sck scr scs sct sda sdb sdc sdd sdf sdk sdr sds sdt sfa sfb sfc sfd sff sfk sfr sfs sft sk- ska skb skc skd skf skk skr sks skt sr- sra srb src srd srf srk srr srs srt ss- ssa ssb ssc ssd ssf ssk ssr sss sst sta stb stc std stf stk str sts stt taa tab tac tad taf tak tar tas tat tba tbb tbc tbd tbf tbk tbr tbs tbt tca tcb tcc tcd tcf tck tcr tcs tct tda tdb tdc tdd tdf tdk tdr tds tdt tfa tfb tfc tfd tff tfk tfr tfs tft tka tkb tkc tkk tkr tks tkt tra trb trc trd trf trk trr trs trt tsa tsb tsc tsd tsf tsk tsr tss tst tta ttb ttc ttd ttf ttk ttr tts ttt