-er a-a a-b aaa aab aad aae aao aap aar ab- aba abb abd abe abo abp abr ad- ada adb add ade ado adp adr aea aeb aed aee aeo aep aer aoa aob aod aoe aoo aop aor ap- apa apb apd ape apo app apr ar- ara arb ard are aro arp arr b-p baa bab bad bae bao bap bar bba bbb bbd bbe bbo bbp bbr bda bdb bdd bde bdo bdp bdr be- bea beb bed bee beo bep ber boa bob bod boe boo bop bor bpa bpb bpd bpe bpo bpp bpr bra brb brd bre bro brp brr daa dab dad dae dao dap dar dba dbb dbd dbe dbo dbp dbr dda ddb ddd dde ddo ddp ddr de- dea deb ded dee deo dep der doa dob dod doe doo dop dor dpa dpb dpd dpe dpo dpp dpr dra drb drd dre dro drp drr eaa eab ead eae eao eap ear eba ebb ebd ebe ebo ebp ebr ed- eda edb edd ede edo edp edr eea eeb eed eee eeo eep eer eo- eoa eob eod eoe eoo eop eor ep- epa epb epd epe epo epp epr era erb erd ere ero erp err oaa oab oad oae oao oap oar ob- oba obb obd obe obo obp obr oda odb odd ode odo odp odr oea oeb oed oee oeo oep oer oo- ooa oob ood ooo oop oor op- opa opb opd ope opo opp opr or- ora orb ord ore oro orp orr p-p paa pab pad pae pao pap par pba pbb pbd pbe pbo pbp pbr pda pdb pdd pde pdo pdp pdr pea peb ped pee peo pep per poa pob pod poe poo pop por ppa ppb ppd ppe ppo ppp ppr pra prb prd pre pro prp prr ra- raa rab rad rae rao rap rar rba rbb rbd rbe rbo rbp rbr rda rdb rdd rde rdo rdp rdr re- rea reb red ree reo rep rer roa rob rod roe roo rop ror rpa rpb rpd rpe rpo rpp rpr rra rrb rrd rrp rrr