a-a a-b a-t aaa aab aad aak aao aar aas aat ab- aba abb abd abk abo abr abs abt ad- ada adb add adk ado adr ads adt aka akb akd akk ako akr aks aoa aob aod aok aoo aor aos aot ar- ara arb ard ark aro arr ars art as- asa asb asd ask aso asr ass ast at- ata atb atd ato atr ats att baa bab bad bak bao bar bas bat bba bbb bbd bbk bbo bbr bbs bbt bda bdb bdd bdk bdo bdr bds bdt bka bkb bkk bko bkr bks bkt boa bob bod bok boo bor bos bot bra brb brd brk bro brr brs brt bsa bsb bsd bsk bso bsr bss bst bta btb btd btk bto btr bts btt daa dab dad dak dao dar das dat dba dbb dbd dbk dbo dbr dbs dbt dda ddb ddd ddk ddo ddr dds ddt dka dkb dkk dko dkr dks dkt doa dob dod dok doo dor dos dot dra drb drd drk dro drr drs drt dsa dsb dsd dsk dso dsr dss dst dta dtb dtd dtk dto dtr dts dtt k-t ka- kaa kab kad kak kao kar kas kat kba kbb kbd kbk kbo kbr kbs kda kdb kdk kdo kdr kds kdt kkb kkk kkr kks kkt koa kob kod kok koo kor kos kot kra krd krk kro krr krs krt ksa ksb ksd ksk kso ksr kss kst kta ktb ktk kto ktr kts ktt oaa oab oad oak oao oar oas oat ob- oba obb obd obk obo obr obs obt oda odb odd odo odr ods odt oka okb okd okk oko okr oks oo- ooa oob ood ook ooo oor oos oot or- ora orb ord ork oro orr ors ort os- osa osb osd osk oso osr oss ost ot- ota otb otd otk oto otr ots ott ra- raa rab rad rak rao rar ras rat rba rbb rbd rbk rbo rbr rbs rbt rda rdb rdd rdo rdr rds rdt rkb rkk rko rks rkt roa rob rod rok roo ror ros rot rra rrb rrd rrk rrr rrs rrt rsa rsb rsd rsk rso rsr rss rst rta rtb rtd rtk rto rtr rts rtt saa sab sad sak sao sar sas sat sba sbb sbd sbk sbo sbr sbs sbt sda sdb sdd sdk sdo sdr sds sdt sk- ska skb skd skk sko skr sks skt soa sob sod sok soo sor sos sot sr- sra srb srd srk sro srr srs srt ss- ssa ssb ssd ssk sso ssr sss sst sta stb std stk sto str sts stt taa tab tad tak tao tar tas tat tba tbb tbd tbk tbo tbr tbs tbt tda tdb tdd tdk tdo tdr tds tdt tka tkb tkk tko tkr tks tkt to- toa tob tod tok too tor tos tot tra trb trd trk tro trr trs trt tsa tsb tsd tsk tso tsr tss tst tta ttb ttd ttk tto ttr tts ttt