-er a-a a-b aaa aab aad aae aap aar ab- aba abb abd abe abp abr ad- ada adb add ade adp adr aea aeb aed aee aep aer ap- apa apb apd ape app apr ar- ara arb ard are arp arr b-p baa bab bad bae bap bar bba bbb bbd bbe bbp bbr bda bdb bdd bde bdp bdr be- bea beb bed bee bep ber bpa bpb bpd bpe bpp bpr bra brb brd bre brp brr daa dab dad dae dap dar dba dbb dbd dbe dbp dbr dda ddb ddd dde ddp ddr de- dea deb ded dee dep der dpa dpb dpd dpe dpp dpr dra drb drd dre drp drr eaa eab ead eae eap ear eba ebb ebd ebe ebp ebr ed- eda edb edd ede edp edr eea eeb eed eee eep eer ep- epa epb epd epe epp epr era erb erd ere erp err p-p paa pab pad pae pap par pba pbb pbd pbe pbp pbr pda pdb pdd pde pdp pdr pea peb ped pee pep per ppa ppb ppd ppe ppp ppr pra prb prd pre prp prr ra- raa rab rad rae rap rar rba rbb rbd rbe rbp rbr rda rdb rdd rde rdp rdr re- rea reb red ree rep rer rpa rpb rpd rpe rpp rpr rra rrb rrd rrp rrr