a-a a-b aaa aab aad aao aap aar ab- aba abb abd abo abp abr ad- ada adb add ado adp adr aoa aob aod aoo aop aor ap- apa apb apd apo app apr ar- ara arb ard aro arp arr b-p baa bab bad bao bap bar bba bbb bbd bbo bbp bbr bda bdb bdd bdo bdp bdr boa bob bod boo bop bor bpa bpb bpd bpo bpp bpr bra brb brd bro brp brr daa dab dad dao dap dar dba dbb dbd dbo dbp dbr dda ddb ddd ddo ddp ddr doa dob dod doo dop dor dpa dpb dpd dpo dpp dpr dra drb drd dro drp drr oaa oab oad oao oap oar ob- oba obb obd obo obp obr oda odb odd odo odp odr oo- ooa oob ood ooo oop oor op- opa opb opd opo opp opr or- ora orb ord oro orp orr p-p paa pab pad pao pap par pba pbb pbd pbo pbp pbr pda pdb pdd pdo pdp pdr poa pob pod poo pop por ppa ppb ppd ppo ppp ppr pra prb prd pro prp prr ra- raa rab rad rao rap rar rba rbb rbd rbo rbp rbr rda rdb rdd rdo rdp rdr roa rob rod roo rop ror rpa rpb rpd rpo rpp rpr rra rrb rrd rrp rrr