a-a a-b a-t aaa aab aad aaf aao aar aas aat ab- aba abb abd abf abo abr abs abt ad- ada adb add adf ado adr ads adt af- afa afb afd aff afo afr afs aft aoa aob aod aof aoo aor aos aot ar- ara arb ard arf aro arr ars art as- asa asb asd asf aso asr ass ast at- ata atb atd atf ato atr ats att baa bab bad baf bao bar bas bat bba bbb bbd bbf bbo bbr bbs bbt bda bdb bdd bdf bdo bdr bds bdt bfa bfb bfd bff bfo bfr bfs bft boa bob bod bof boo bor bos bot bra brb brd brf bro brr brs brt bsa bsb bsd bsf bso bsr bss bst bta btb btd btf bto btr bts btt daa dab dad daf dao dar das dat dba dbb dbd dbf dbo dbr dbs dbt dda ddb ddd ddf ddo ddr dds ddt dfa dfb dfd dff dfo dfr dfs dft doa dob dod dof doo dor dos dot dra drb drd dro drr drs drt dsa dsb dsd dsf dso dsr dss dst dta dtb dtd dtf dto dtr dts dtt faa fab fad faf fao far fas fat fba fbb fbd fbf fbo fbr fbs fbt fda fdb fdd fdf fdo fdr fds fdt ffa ffd fff ffo ffr ffs fft foa fob fof foo for fos fot fra frb frd frf fro frr frs frt fsa fsb fsd fsf fso fsr fss fst fta ftb ftd ftf fto ftr fts ftt oaa oab oad oaf oao oar oas oat ob- oba obb obd obf obo obr obs obt oda odb odd odf odo odr ods odt of- ofa ofb ofd off ofo ofr ofs oft oo- ooa oob ood oof ooo oor oos oot or- ora orb ord orf oro orr ors ort os- osa osb osd osf oso osr oss ost ot- ota otb otd otf oto otr ots ott ra- raa rab rad raf rao rar ras rat rba rbb rbd rbf rbo rbr rbs rbt rda rdb rdd rdf rdo rdr rds rdt rfa rfb rfd rff rfo rfr rfs rft roa rob rod rof roo ror ros rot rra rrb rrd rrf rrr rrs rrt rsa rsb rsd rsf rso rsr rss rst rta rtb rtd rtf rto rtr rts rtt saa sab sad saf sao sar sas sat sba sbb sbd sbf sbo sbr sbs sbt sda sdb sdd sdf sdo sdr sds sdt sfa sfb sfd sff sfo sfr sfs sft soa sob sod sof soo sor sos sot sr- sra srb srd srf sro srr srs srt ss- ssa ssb ssd ssf sso ssr sss sst sta stb std stf sto str sts stt taa tab tad taf tao tar tas tat tba tbb tbd tbf tbo tbr tbs tbt tda tdb tdd tdf tdo tdr tds tdt tfa tfb tfd tff tfo tfr tfs tft to- toa tob tod tof too tor tos tot tra trb trd trf tro trr trs trt tsa tsb tsd tsf tso tsr tss tst tta ttb ttd ttf tto ttr tts ttt