a-a a-b a-t aaa aab aap aar aas aat ab- aba abb abp abr abs abt ap- apa apb app apr aps apt ar- ara arb arp arr ars art as- asa asb asp asr ass ast at- ata atb atp atr ats att b-p baa bab bap bar bas bat bba bbb bbp bbr bbs bbt bpa bpb bpp bpr bps bpt bra brb brp brr brs brt bsa bsb bsp bsr bss bst bta btb btp btr bts btt p-p paa pab pap par pas pat pba pbb pbp pbr pbs pbt ppa ppb ppp ppr pps ppt pra prb prp prr prs prt ps- psa psb psp psr pss pst pt- pta ptb ptp ptr pts ptt ra- raa rab rap rar ras rat rba rbb rbp rbr rbs rbt rpa rpb rpp rpr rps rpt rra rrb rrp rrr rrs rrt rsa rsb rsp rsr rss rst rta rtb rtp rtr rts rtt saa sab sap sar sas sat sba sbb sbp sbr sbs sbt spa spb spp spr sps spt sr- sra srb srp srr srs srt ss- ssa ssb ssp ssr sss sst sta stb stp str sts stt taa tab tap tar tas tat tba tbb tbp tbr tbs tbt tpa tpb tpp tpr tps tpt tra trb trp trr trs trt tsa tsb tsp tsr tss tst tta ttb ttp ttr tts ttt