a-a a-b aaa aab aak aam aar ab- aba abb abk abm abr aka akb akk akm akr ama amb amk amm amr ar- ara arb ark arm arr baa bab bak bam bar bba bbb bbk bbm bbr bka bkb bkk bkm bkr bma bmb bmk bmm bmr bra brb brk brm brr ka- kaa kab kak kam kar kba kbb kbk kbm kbr kkb kkk kkm kkr kma kmb kmk kmm kra krk krr m-r maa mab mak mam mar mba mbb mbk mbm mbr mka mkb mkk mkm mkr mma mmb mmk mmm mmr mra mrb mrk mrm mrr ra- raa rab rak ram rar rba rbb rbk rbm rbr rkb rkk rkm rma rmb rmm rmr rra rrb rrk rrm rrr