a-a a-b a-c aaa aab aac aak aam aar ab- aba abb abc abk abm abr ac- aca acb acc ack acm acr aka akb akc akk akm akr ama amb amc amk amm amr ar- ara arb arc ark arm arr baa bab bac bak bam bar bba bbb bbc bbk bbm bbr bca bcb bcc bck bcm bcr bka bkb bkc bkk bkm bkr bma bmb bmc bmk bmm bmr bra brb brk brm brr c-- caa cab cac cak cam car cba cbb cbc cbk cbm cbr cca ccb ccc cck ccm ccr cka ckb ckc ckm cma cmb cmc cmk cmm cmr cra crb crc crk crm crr ka- kaa kab kac kak kam kar kba kbb kbc kbk kbm kbr kca kcb kcc kck kcm kcr kkb kkc kkk kkm kkr kma kmb kmc kmk kmm kra krc krk krr m-r maa mab mac mak mam mar mba mbb mbc mbk mbm mbr mc- mca mcb mcc mck mcm mcr mka mkb mkc mkk mkm mkr mma mmb mmc mmk mmm mmr mra mrb mrc mrk mrm mrr ra- raa rab rac rak ram rar rba rbb rbc rbk rbm rbr rca rcb rcc rcm rcr rkb rkc rkk rkm rma rmb rmc rmm rmr rra rrb rrc rrk rrm rrr