a-a a-b aaa aab aam aap aar ab- aba abb abm abp abr ama amb amm amp amr ap- apa apb apm app apr ar- ara arb arm arp arr b-p baa bab bam bap bar bba bbb bbm bbp bbr bma bmb bmm bmp bmr bpa bpb bpm bpp bpr bra brb brm brp brr m-r maa mab mam map mar mba mbb mbm mbp mbr mma mmb mmm mmp mmr mpa mpb mpm mpp mpr mra mrb mrm mrp mrr p-p paa pab pam pap par pba pbb pbm pbp pbr pma pmb pmm pmp pmr ppa ppb ppm ppp ppr pra prb prm prp prr ra- raa rab ram rap rar rba rbb rbm rbp rbr rma rmb rmm rmp rmr rpa rpb rpm rpp rpr rra rrb rrm rrp rrr