a-a a-b a-t aaa aab aad aao aap aar aat ab- aba abb abd abo abp abr abt ad- ada adb add ado adp adr adt aoa aob aod aoo aop aor aot ap- apa apb apd apo app apr apt ar- ara arb ard aro arp arr art at- ata atb atd ato atp atr att b-p baa bab bad bao bap bar bat bba bbb bbd bbo bbp bbr bbt bda bdb bdd bdo bdp bdr bdt boa bob bod boo bop bor bot bpa bpb bpd bpo bpp bpr bpt bra brb brd bro brp brr brt bta btb btd bto btp btr btt daa dab dad dao dap dar dat dba dbb dbd dbo dbp dbr dbt dda ddb ddd ddo ddp ddr ddt doa dob dod doo dop dor dot dpa dpb dpd dpo dpp dpr dpt dra drb drd dro drp drr drt dta dtb dtd dto dtp dtr dtt oaa oab oad oao oap oar oat ob- oba obb obd obo obp obr obt oda odb odd odo odp odr odt oo- ooa oob ood ooo oop oor oot op- opa opb opd opo opp opr opt or- ora orb ord oro orp orr ort ot- ota otb otd oto otp otr ott p-p paa pab pad pao pap par pat pba pbb pbd pbo pbp pbr pbt pda pdb pdd pdo pdp pdr pdt poa pob pod poo pop por pot ppa ppb ppd ppo ppp ppr ppt pra prb prd pro prp prr prt pt- pta ptb ptd pto ptp ptr ptt ra- raa rab rad rao rap rar rat rba rbb rbd rbo rbp rbr rbt rda rdb rdd rdo rdp rdr rdt roa rob rod roo rop ror rot rpa rpb rpd rpo rpp rpr rpt rra rrb rrd rrp rrr rrt rta rtb rtd rto rtp rtr rtt taa tab tad tao tap tar tat tba tbb tbd tbo tbp tbr tbt tda tdb tdd tdo tdp tdr tdt to- toa tob tod too top tor tot tpa tpb tpd tpo tpp tpr tpt tra trb trd tro trp trr trt tta ttb ttd tto ttp ttr ttt