-er a-a a-b a-c a-t aaa aab aac aae aak aap aar aat ab- aba abb abc abe abk abp abr abt ac- aca acb acc ace ack acp acr act aea aeb aec aee aek aep aer aet aka akb akc ake akk akp akr ap- apa apb apc ape apk app apr apt ar- ara arb arc are ark arp arr art at- ata atb atc ate atp atr att b-p baa bab bac bae bak bap bar bat bba bbb bbc bbe bbk bbp bbr bbt bca bcb bcc bce bck bcp bcr bct be- bea beb bec bee bek bep ber bet bka bkb bkc bke bkk bkp bkr bkt bpa bpb bpc bpe bpp bpr bpt bra brb bre brk brp brr brt bta btb btc bte btk btp btr btt c-- caa cab cac cae cak cap car cat cba cbb cbc cbe cbk cbp cbr cbt cca ccb ccc cce cck ccp ccr cct ce- cea ceb cec cee cek cep cer cet cka ckb ckc ckt cpa cpb cpc cpe cpk cpp cpr cpt cra crb crc cre crk crp crr crt cta ctb ctc cte ctk ctp ctr ctt eaa eab eac eae eak eap ear eat eba ebb ebc ebe ebk ebp ebr ebt ec- eca ecb ecc ece eck ecr ect eea eeb eec eee eek eep eer eet eka ekb ekc eke ekp ekr ekt ep- epa epb epc epe epp epr ept era erb erc ere erk erp err ert eta etb etc ete etk etp etr ett k-t ka- kaa kab kac kae kak kap kar kat kba kbb kbc kbe kbk kbp kbr kca kcb kcc kce kck kcp kcr kct ke- kea keb kec kee kek kep ker ket kkb kkc kke kkk kkp kkr kkt kpa kpc kpe kpk kpp kpr kpt kra krc krk krp krr krt kta ktb ktc kte ktk ktp ktr ktt p-p paa pab pac pae pak pap par pat pba pbb pbc pbe pbk pbp pbr pbt pca pcb pcc pce pck pcp pcr pct pea peb pec pee pek pep per pet pka pkb pkc pke pkp pkr pkt ppa ppb ppc ppe ppk ppp ppr ppt pra prb prc pre prk prp prr prt pt- pta ptb ptc pte ptk ptp ptr ptt ra- raa rab rac rae rak rap rar rat rba rbb rbc rbe rbk rbp rbr rbt rca rcb rcc rce rcp rcr rct re- rea reb rec ree rek rep rer ret rkb rkc rke rkk rkp rkt rpa rpb rpc rpe rpk rpp rpr rpt rra rrb rrc rrk rrp rrr rrt rta rtb rtc rte rtk rtp rtr rtt taa tab tac tae tak tap tar tat tba tbb tbc tbe tbk tbp tbr tbt tca tcb tcc tce tck tcp tcr tct te- tea teb tec tee tek tep ter tet tka tkb tkc tke tkk tkp tkr tkt tpa tpb tpc tpe tpk tpp tpr tpt tra trb trc tre trk trp trr trt tta ttb ttc tte ttk ttp ttr ttt