a-a a-b a-c aaa aab aac aam aar ab- aba abb abc abm abr ac- aca acb acc acm acr ama amb amc amm amr ar- ara arb arc arm arr baa bab bac bam bar bba bbb bbc bbm bbr bca bcb bcc bcm bcr bma bmb bmc bmm bmr bra brb brm brr c-- caa cab cac cam car cba cbb cbc cbm cbr cca ccb ccc ccm ccr cma cmb cmc cmm cmr cra crb crc crm crr m-r maa mab mac mam mar mba mbb mbc mbm mbr mc- mca mcb mcc mcm mcr mma mmb mmc mmm mmr mra mrb mrc mrm mrr ra- raa rab rac ram rar rba rbb rbc rbm rbr rca rcb rcc rcm rcr rma rmb rmc rmm rmr rra rrb rrc rrm rrr