-er a-a a-b a-i a-t aaa aab aae aai aap aar aat ab- aba abb abe abi abp abr abt aea aeb aee aei aep aer aet ai- aia aib aie aii aip air ait ap- apa apb ape api app apr apt ar- ara arb are ari arp arr art at- ata atb ate ati atp atr att b-p baa bab bae bai bap bar bat bba bbb bbe bbi bbp bbr bbt be- bea beb bee bei bep ber bet bi- bia bib bie bii bip bir bit bpa bpb bpe bpi bpp bpr bpt bra brb bre bri brp brr brt bta btb bte bti btp btr btt eaa eab eae eai eap ear eat eba ebb ebe ebi ebp ebr ebt eea eeb eee eep eer eet eia eib eie eii eip eir eit ep- epa epb epe epi epp epr ept era erb ere eri erp err ert eta etb ete eti etp etr ett ia- iaa iab iae iai iap iar iat iba ibb ibe ibi ibp ibr ibt ie- iea iee iei iep ier iet iia iib iie iii iip iir iit ipa ipb ipe ipi ipp ipr ipt ir- ira irb ire iri irp irr irt ita itb ite iti itp itt p-p paa pab pae pai pap par pat pba pbb pbe pbi pbp pbr pbt pea peb pee pei pep per pet pia pib pie pii pip pir pit ppa ppb ppe ppi ppp ppr ppt pra prb pre pri prp prr prt pt- pta ptb pte pti ptp ptr ptt ra- raa rab rae rai rap rar rat rba rbb rbe rbi rbp rbr rbt re- rea reb ree rei rep rer ret ria rib rie rii rip rir rit rpa rpb rpe rpi rpp rpr rpt rra rrb rri rrp rrr rrt rta rtb rte rti rtp rtr rtt taa tab tae tai tap tar tat tba tbb tbe tbi tbp tbr tbt te- tea teb tee tei tep ter tet tia tib tie tii tip tir tit tpa tpb tpe tpi tpp tpr tpt tra trb tre tri trp trr trt tta ttb tte tti ttp ttr ttt