a-a a-b a-t aaa aab aam aao aar aas aat ab- aba abb abm abo abr abs abt ama amb amm amo amr ams amt aoa aob aom aoo aor aos aot ar- ara arb arm aro arr ars art as- asa asb asm aso asr ass ast at- ata atb atm ato atr ats att baa bab bam bao bar bas bat bba bbb bbm bbo bbr bbs bbt bma bmb bmm bmo bmr bms bmt boa bob bom boo bor bos bot bra brb brm bro brr brs brt bsa bsb bsm bso bsr bss bst bta btb btm bto btr bts btt m-o m-r maa mab mam mao mar mas mat mba mbb mbm mbo mbr mbs mbt mma mmb mmm mmo mmr mms mmt moa mob mom moo mor mos mot mra mrb mrm mro mrr mrs mrt msa msb msm mso msr mss mst mta mtb mtm mto mtr mts mtt oaa oab oam oao oar oas oat ob- oba obb obm obo obr obs obt om- oma omb omm omo omr oms omt oo- ooa oob oom ooo oor oos oot or- ora orb orm oro orr ors ort os- osa osb osm oso osr oss ost ot- ota otb otm oto otr ots ott ra- raa rab ram rao rar ras rat rba rbb rbm rbo rbr rbs rbt rma rmb rmm rmo rmr rms rmt roa rob rom roo ror ros rot rra rrb rrm rrr rrs rrt rsa rsb rsm rso rsr rss rst rta rtb rtm rto rtr rts rtt saa sab sam sao sar sas sat sba sbb sbm sbo sbr sbs sbt sma smb smm smo smr sms smt soa sob som soo sor sos sot sr- sra srb srm sro srr srs srt ss- ssa ssb ssm sso ssr sss sst sta stb stm sto str sts stt taa tab tam tao tar tas tat tba tbb tbm tbo tbr tbs tbt tma tmb tmm tmo tmr tms tmt to- toa tob tom too tor tos tot tra trb trm tro trr trs trt tsa tsb tsm tso tsr tss tst tta ttb ttm tto ttr tts ttt