a-a a-b a-t aaa aab aad aao aar aas aat ab- aba abb abd abo abr abs abt ad- ada adb add ado adr ads adt aoa aob aod aoo aor aos aot ar- ara arb ard aro arr ars art as- asa asb asd aso asr ass ast at- ata atb atd ato atr ats att baa bab bad bao bar bas bat bba bbb bbd bbo bbr bbs bbt bda bdb bdd bdo bdr bds bdt boa bob bod boo bor bos bot bra brb brd bro brr brs brt bsa bsb bsd bso bsr bss bst bta btb btd bto btr bts btt daa dab dad dao dar das dat dba dbb dbd dbo dbr dbs dbt dda ddb ddd ddo ddr dds ddt doa dob dod doo dor dos dot dra drb drd dro drr drs drt dsa dsb dsd dso dsr dss dst dta dtb dtd dto dtr dts dtt oaa oab oad oao oar oas oat ob- oba obb obd obo obr obs obt oda odb odd odo odr ods odt oo- ooa oob ood ooo oor oos oot or- ora orb ord oro orr ors ort os- osa osb osd oso osr oss ost ot- ota otb otd oto otr ots ott ra- raa rab rad rao rar ras rat rba rbb rbd rbo rbr rbs rbt rda rdb rdd rdo rdr rds rdt roa rob rod roo ror ros rot rra rrb rrd rrr rrs rrt rsa rsb rsd rso rsr rss rst rta rtb rtd rto rtr rts rtt saa sab sad sao sar sas sat sba sbb sbd sbo sbr sbs sbt sda sdb sdd sdo sdr sds sdt soa sob sod soo sor sos sot sr- sra srb srd sro srr srs srt ss- ssa ssb ssd sso ssr sss sst sta stb std sto str sts stt taa tab tad tao tar tas tat tba tbb tbd tbo tbr tbs tbt tda tdb tdd tdo tdr tds tdt to- toa tob tod too tor tos tot tra trb trd tro trr trs trt tsa tsb tsd tso tsr tss tst tta ttb ttd tto ttr tts ttt