-er a-a a-b aaa aab aae aag aap aar ab- aba abb abe abg abp abr aea aeb aee aeg aep aer ag- aga agb age agg agp agr ap- apa apb ape apg app apr ar- ara arb are arg arp arr b-p baa bab bae bag bap bar bba bbb bbe bbg bbp bbr be- bea beb bee beg bep ber bga bgb bge bgg bgp bgr bpa bpb bpe bpg bpp bpr bra brb bre brg brp brr eaa eab eae eag eap ear eba ebb ebe ebg ebp ebr eea eeb eee eeg eep eer ega egb ege egg egp egr ep- epa epb epe epg epp epr era erb ere erg erp err g-p gaa gab gae gag gap gar gba gbe gbg gbp gbr ge- gea geb gee geg gep ger gga ggb ggg ggp ggr gpa gpb gpe gpg gpp gpr gra grb gre grg grp grr p-p paa pab pae pag pap par pba pbb pbe pbg pbp pbr pea peb pee peg pep per pga pgb pge pgg pgp pgr ppa ppb ppe ppg ppp ppr pra prb pre prg prp prr ra- raa rab rae rag rap rar rba rbb rbe rbg rbp rbr re- rea reb ree reg rep rer rga rgb rge rgg rgp rgr rpa rpb rpe rpg rpp rpr rra rrb rrg rrp rrr