a-a a-b a-i a-t aaa aab aai aap aar aat aax ab- aba abb abi abp abr abt abx ai- aia aib aii aip air ait aix ap- apa apb api app apr apt apx ar- ara arb ari arp arr art arx at- ata atb ati atp atr att atx ax- axa axi axp axr axt axx b-p baa bab bai bap bar bat bax bba bbb bbi bbp bbr bbt bbx bi- bia bib bii bip bir bit bix bpa bpb bpi bpp bpr bpt bpx bra brb bri brp brr brt brx bta btb bti btp btr btt btx bxb bxi bxx ia- iaa iab iai iap iar iat iba ibb ibi ibp ibr ibt ibx iia iib iii iip iir iit iix ipa ipb ipi ipp ipr ipt ipx ir- ira irb iri irp irr irt irx ita itb iti itp itt itx ixi p-p paa pab pai pap par pat pax pba pbb pbi pbp pbr pbt pbx pia pib pii pip pir pit pix ppa ppb ppi ppp ppr ppt ppx pra prb pri prp prr prt prx pt- pta ptb pti ptp ptr ptt ptx pxr pxt ra- raa rab rai rap rar rat rax rba rbb rbi rbp rbr rbt rbx ria rib rii rip rir rit rix rpa rpb rpi rpp rpr rpt rpx rra rrb rri rrp rrr rrt rta rtb rti rtp rtr rtt rtx rxp rxr t-x taa tab tai tap tar tat tax tba tbb tbi tbp tbr tbt tia tib tii tip tir tit tix tpa tpb tpi tpp tpr tpt tpx tra trb tri trp trr trt trx tta ttb tti ttp ttr ttt ttx txi txt xaa xap xar xat xbr xbx xia xii xit xix xpa xpb xpp xpt xrt xrx xti xtp xtr xtx xxi xxp xxx