a-a a-b a-c a-t aaa aab aac aam aar aat ab- aba abb abc abm abr abt ac- aca acb acc acm acr act ama amb amc amm amr amt ar- ara arb arc arm arr art at- ata atb atc atm atr att baa bab bac bam bar bat bba bbb bbc bbm bbr bbt bca bcb bcc bcm bcr bct bma bmb bmc bmm bmr bmt bra brb brm brr brt bta btb btc btm btr btt c-- caa cab cac cam car cat cba cbb cbc cbm cbr cbt cca ccb ccc ccm ccr cct cma cmb cmc cmm cmr cmt cra crb crc crm crr crt cta ctb ctc ctm ctr ctt m-r maa mab mac mam mar mat mba mbb mbc mbm mbr mbt mc- mca mcb mcc mcm mcr mct mma mmb mmc mmm mmr mmt mra mrb mrc mrm mrr mrt mta mtb mtc mtm mtr mtt ra- raa rab rac ram rar rat rba rbb rbc rbm rbr rbt rca rcb rcc rcm rcr rct rma rmb rmc rmm rmr rmt rra rrb rrc rrm rrr rrt rta rtb rtc rtm rtr rtt taa tab tac tam tar tat tba tbb tbc tbm tbr tbt tca tcb tcc tcm tcr tct tma tmb tmc tmm tmr tmt tra trb trc trm trr trt tta ttb ttc ttm ttr ttt