a-a a-b a-i a-t aaa aab aai aao aap aas aat ab- aba abb abi abo abp abs abt ai- aia aib aii aio aip ais ait aoa aob aoi aoo aop aos aot ap- apa apb api apo app aps apt as- asa asb asi aso asp ass ast at- ata atb ati ato atp ats att b-p baa bab bai bao bap bas bat bba bbb bbi bbo bbp bbs bbt bi- bia bib bii bio bip bis bit boa bob boi boo bop bos bot bpa bpb bpi bpo bpp bps bpt bsa bsb bsi bso bsp bss bst bta btb bti bto btp bts btt ia- iaa iab iai iao iap ias iat iba ibb ibi ibo ibp ibs ibt iia iib iii iio iip iis iit io- ioa iob ioi ioo iop ios iot ipa ipb ipi ipo ipp ips ipt is- isa isb isi iso isp iss ist ita itb iti ito itp its itt o-i oaa oab oai oao oap oas oat ob- oba obb obi obo obp obs obt oia oib oii oio oip ois oit oo- ooa oob ooi ooo oop oos oot op- opa opb opi opo opp ops opt os- osa osb osi oso osp oss ost ot- ota otb oti oto otp ots ott p-p paa pab pai pao pap pas pat pba pbb pbi pbo pbp pbs pbt pia pib pii pio pip pis pit poa pob poi poo pop pos pot ppa ppb ppi ppo ppp pps ppt ps- psa psb psi pso psp pss pst pt- pta ptb pti pto ptp pts ptt saa sab sai sao sap sas sat sba sbb sbi sbo sbp sbs sbt sia sib sii sio sip sis sit soa sob soi soo sop sos sot spa spb spi spo spp sps spt ss- ssa ssb ssi sso ssp sss sst sta stb sti sto stp sts stt taa tab tai tao tap tas tat tba tbb tbi tbo tbp tbs tbt tia tib tii tio tip tis tit to- toa tob toi too top tos tot tpa tpb tpi tpo tpp tps tpt tsa tsb tsi tso tsp tss tst tta ttb tti tto ttp tts ttt