-er a-a a-b a-c a-t aaa aab aac aae aam aar aat ab- aba abb abc abe abm abr abt ac- aca acb acc ace acm acr act aea aeb aec aee aem aer aet ama amb amc ame amm amr amt ar- ara arb arc are arm arr art at- ata atb atc ate atm atr att baa bab bac bae bam bar bat bba bbb bbc bbe bbm bbr bbt bca bcb bcc bce bcm bcr bct be- bea beb bec bee bem ber bet bma bmb bmc bme bmm bmr bmt bra brb bre brm brr brt bta btb btc bte btm btr btt c-- caa cab cac cae cam car cat cba cbb cbc cbe cbm cbr cbt cca ccb ccc cce ccm ccr cct ce- cea ceb cec cee cem cer cet cma cmb cmc cme cmm cmr cmt cra crb crc cre crm crr crt cta ctb ctc cte ctm ctr ctt eaa eab eac eae eam ear eat eba ebb ebc ebe ebm ebr ebt ec- eca ecb ecc ece ecm ecr ect eea eeb eec eee eem eer eet em- ema emb emc eme emm emr emt era erb erc ere erm err ert eta etb etc ete etm etr ett m-r maa mab mac mae mam mar mat mba mbb mbc mbe mbm mbr mbt mc- mca mcb mcc mce mcm mcr mct mea meb mec mee mem mer met mma mmb mmc mme mmm mmr mmt mra mrb mrc mre mrm mrr mrt mta mtb mtc mte mtm mtr mtt ra- raa rab rac rae ram rar rat rba rbb rbc rbe rbm rbr rbt rca rcb rcc rce rcm rcr rct re- rea reb rec ree rem rer ret rma rmb rmc rme rmm rmr rmt rra rrb rrc rrm rrr rrt rta rtb rtc rte rtm rtr rtt taa tab tac tae tam tar tat tba tbb tbc tbe tbm tbr tbt tca tcb tcc tce tcm tcr tct te- tea teb tec tee tem ter tet tma tmb tmc tme tmm tmr tmt tra trb trc tre trm trr trt tta ttb ttc tte ttm ttr ttt