a-a a-b a-t aaa aab aad aar aas aat aau ab- aba abb abd abr abs abt abu ad- ada adb add adr ads adt adu ar- ara arb ard arr ars art aru as- asa asb asd asr ass ast asu at- ata atb atd atr ats att atu au- aua aub aud aur aus aut b-u baa bab bad bar bas bat bau bba bbb bbd bbr bbs bbt bbu bda bdb bdd bdr bds bdt bdu bra brb brd brr brs brt bru bsa bsb bsd bsr bss bst bsu bta btb btd btr bts btt btu bua bub bud bur bus but buu daa dab dad dar das dat dau dba dbb dbd dbr dbs dbt dbu dda ddb ddd ddr dds ddt ddu dra drb drd drr drs drt dru dsa dsb dsd dsr dss dst dsu dta dtb dtd dtr dts dtt dtu dua dub dud dur dus dut ra- raa rab rad rar ras rat rau rba rbb rbd rbr rbs rbt rbu rda rdb rdd rdr rds rdt rdu rra rrb rrd rrr rrs rrt rru rsa rsb rsd rsr rss rst rsu rta rtb rtd rtr rts rtt rtu rua rub rud rur rus rut ruu saa sab sad sar sas sat sau sba sbb sbd sbr sbs sbt sbu sda sdb sdd sdr sds sdt sdu sr- sra srb srd srr srs srt ss- ssa ssb ssd ssr sss sst ssu sta stb std str sts stt stu sua sub sud sur sus sut suu taa tab tad tar tas tat tau tba tbb tbd tbr tbs tbt tbu tda tdb tdd tdr tds tdt tdu tra trb trd trr trs trt tru tsa tsb tsd tsr tss tst tsu tta ttb ttd ttr tts ttt ttu tua tub tud tur tus tut tuu ua- uaa uab uad uar uas uat uau uba ubb ubr ubs ubt ubu uda udb udd udr uds udt udu ur- ura urb urd urr urs urt uru usa usb usd usr uss ust usu uta utb utd utr uts utt utu uua uur uus uut uuu