a-a a-b a-i a-t aaa aab aai aap aas aat ab- aba abb abi abp abs abt ai- aia aib aii aip ais ait ap- apa apb api app aps apt as- asa asb asi asp ass ast at- ata atb ati atp ats att b-p baa bab bai bap bas bat bba bbb bbi bbp bbs bbt bi- bia bib bii bip bis bit bpa bpb bpi bpp bps bpt bsa bsb bsi bsp bss bst bta btb bti btp bts btt ia- iaa iab iai iap ias iat iba ibb ibi ibp ibs ibt iia iib iii iip iis iit ipa ipb ipi ipp ips ipt is- isa isb isi isp iss ist ita itb iti itp its itt p-p paa pab pai pap pas pat pba pbb pbi pbp pbs pbt pia pib pii pip pis pit ppa ppb ppi ppp pps ppt ps- psa psb psi psp pss pst pt- pta ptb pti ptp pts ptt saa sab sai sap sas sat sba sbb sbi sbp sbs sbt sia sib sii sip sis sit spa spb spi spp sps spt ss- ssa ssb ssi ssp sss sst sta stb sti stp sts stt taa tab tai tap tas tat tba tbb tbi tbp tbs tbt tia tib tii tip tis tit tpa tpb tpi tpp tps tpt tsa tsb tsi tsp tss tst tta ttb tti ttp tts ttt