-er a-a a-b a-c aaa aab aac aae aak aam aar ab- aba abb abc abe abk abm abr ac- aca acb acc ace ack acm acr aea aeb aec aee aek aem aer aka akb akc ake akk akm akr ama amb amc ame amk amm amr ar- ara arb arc are ark arm arr baa bab bac bae bak bam bar bba bbb bbc bbe bbk bbm bbr bca bcb bcc bce bck bcm bcr be- bea beb bec bee bek bem ber bka bkb bkc bke bkk bkm bkr bma bmb bmc bme bmk bmm bmr bra brb bre brk brm brr c-- caa cab cac cae cak cam car cba cbb cbc cbe cbk cbm cbr cca ccb ccc cce cck ccm ccr ce- cea ceb cec cee cek cem cer cka ckb ckc ckm cma cmb cmc cme cmk cmm cmr cra crb crc cre crk crm crr eaa eab eac eae eak eam ear eba ebb ebc ebe ebk ebm ebr ec- eca ecb ecc ece eck ecm ecr eea eeb eec eee eek eem eer eka ekb ekc eke ekr em- ema emb emc eme emk emm emr era erb erc ere erk erm err ka- kaa kab kac kae kak kam kar kba kbb kbc kbe kbk kbm kbr kca kcb kcc kce kck kcm kcr ke- kea keb kec kee kek kem ker kkb kkc kke kkk kkm kkr kma kmb kmc kme kmk kmm kra krc krk krr m-r maa mab mac mae mak mam mar mba mbb mbc mbe mbk mbm mbr mc- mca mcb mcc mce mck mcm mcr mea meb mec mee mek mem mer mka mkb mkc mke mkk mkm mkr mma mmb mmc mme mmk mmm mmr mra mrb mrc mre mrk mrm mrr ra- raa rab rac rae rak ram rar rba rbb rbc rbe rbk rbm rbr rca rcb rcc rce rcm rcr re- rea reb rec ree rek rem rer rkb rkc rke rkk rkm rma rmb rmc rme rmm rmr rra rrb rrc rrk rrm rrr