a-a a-b a-t aaa aab aad aaf aak aao aar aas aat ab- aba abb abd abf abk abo abr abs abt ad- ada adb add adf adk ado adr ads adt af- afa afb afd aff afk afo afr afs aft aka akb akd akk ako akr aks aoa aob aod aof aok aoo aor aos aot ar- ara arb ard arf ark aro arr ars art as- asa asb asd asf ask aso asr ass ast at- ata atb atd atf ato atr ats att baa bab bad baf bak bao bar bas bat bba bbb bbd bbf bbk bbo bbr bbs bbt bda bdb bdd bdf bdk bdo bdr bds bdt bfa bfb bfd bff bfo bfr bfs bft bka bkb bkf bkk bko bkr bks bkt boa bob bod bof bok boo bor bos bot bra brb brd brf brk bro brr brs brt bsa bsb bsd bsf bsk bso bsr bss bst bta btb btd btf btk bto btr bts btt daa dab dad daf dak dao dar das dat dba dbb dbd dbf dbk dbo dbr dbs dbt dda ddb ddd ddf ddk ddo ddr dds ddt dfa dfb dfd dff dfk dfo dfr dfs dft dka dkb dkk dko dkr dks dkt doa dob dod dof dok doo dor dos dot dra drb drd drk dro drr drs drt dsa dsb dsd dsf dsk dso dsr dss dst dta dtb dtd dtf dtk dto dtr dts dtt faa fab fad faf fak fao far fas fat fba fbb fbd fbf fbk fbo fbr fbs fbt fda fdb fdd fdf fdk fdo fdr fds fdt ffa ffd fff ffk ffo ffr ffs fft fka fkb fkf fkk fkt foa fob fof fok foo for fos fot fra frb frd frf frk fro frr frs frt fsa fsb fsd fsf fsk fso fsr fss fst fta ftb ftd ftf ftk fto ftr fts ftt k-t ka- kaa kab kad kaf kak kao kar kas kat kba kbb kbd kbf kbk kbo kbr kbs kda kdb kdf kdk kdo kdr kds kdt kfa kfd kff kfo kfs kkb kkk kkr kks kkt koa kob kod kof kok koo kor kos kot kra krd krf krk kro krr krs krt ksa ksb ksd ksf ksk kso ksr kss kst kta ktb ktf ktk kto ktr kts ktt oaa oab oad oaf oak oao oar oas oat ob- oba obb obd obf obk obo obr obs obt oda odb odd odf odo odr ods odt of- ofa ofb ofd off ofo ofr ofs oft oka okb okd okk oko okr oks oo- ooa oob ood oof ook ooo oor oos oot or- ora orb ord orf ork oro orr ors ort os- osa osb osd osf osk oso osr oss ost ot- ota otb otd otf otk oto otr ots ott ra- raa rab rad raf rak rao rar ras rat rba rbb rbd rbf rbk rbo rbr rbs rbt rda rdb rdd rdf rdo rdr rds rdt rfa rfb rfd rff rfk rfo rfr rfs rft rkb rkf rkk rko rks rkt roa rob rod rof rok roo ror ros rot rra rrb rrd rrf rrk rrr rrs rrt rsa rsb rsd rsf rsk rso rsr rss rst rta rtb rtd rtf rtk rto rtr rts rtt saa sab sad saf sak sao sar sas sat sba sbb sbd sbf sbk sbo sbr sbs sbt sda sdb sdd sdf sdk sdo sdr sds sdt sfa sfb sfd sff sfk sfo sfr sfs sft sk- ska skb skd skf skk sko skr sks skt soa sob sod sof sok soo sor sos sot sr- sra srb srd srf srk sro srr srs srt ss- ssa ssb ssd ssf ssk sso ssr sss sst sta stb std stf stk sto str sts stt taa tab tad taf tak tao tar tas tat tba tbb tbd tbf tbk tbo tbr tbs tbt tda tdb tdd tdf tdk tdo tdr tds tdt tfa tfb tfd tff tfk tfo tfr tfs tft tka tkb tkk tko tkr tks tkt to- toa tob tod tof tok too tor tos tot tra trb trd trf trk tro trr trs trt tsa tsb tsd tsf tsk tso tsr tss tst tta ttb ttd ttf ttk tto ttr tts ttt