a-a a-b aaa aab aag aap aar ab- aba abb abg abp abr ag- aga agb agg agp agr ap- apa apb apg app apr ar- ara arb arg arp arr b-p baa bab bag bap bar bba bbb bbg bbp bbr bga bgb bgg bgp bgr bpa bpb bpg bpp bpr bra brb brg brp brr g-p gaa gab gag gap gar gba gbg gbp gbr gga ggb ggg ggp ggr gpa gpb gpg gpp gpr gra grb grg grp grr p-p paa pab pag pap par pba pbb pbg pbp pbr pga pgb pgg pgp pgr ppa ppb ppg ppp ppr pra prb prg prp prr ra- raa rab rag rap rar rba rbb rbg rbp rbr rga rgb rgg rgp rgr rpa rpb rpg rpp rpr rra rrb rrg rrp rrr