-er a-a a-b a-c a-t aaa aab aac aae aao aap aar aat ab- aba abb abc abe abo abp abr abt ac- aca acb acc ace aco acp acr act aea aeb aec aee aeo aep aer aet aoa aob aoc aoe aoo aop aor aot ap- apa apb apc ape apo app apr apt ar- ara arb arc are aro arp arr art at- ata atb atc ate ato atp atr att b-p baa bab bac bae bao bap bar bat bba bbb bbc bbe bbo bbp bbr bbt bca bcb bcc bce bco bcp bcr bct be- bea beb bec bee beo bep ber bet boa bob boc boe boo bop bor bot bpa bpb bpc bpe bpo bpp bpr bpt bra brb bre bro brp brr brt bta btb btc bte bto btp btr btt c-- caa cab cac cae cao cap car cat cba cbb cbc cbe cbo cbp cbr cbt cca ccb ccc cce cco ccp ccr cct ce- cea ceb cec cee ceo cep cer cet co- coa cob coc coe coo cop cor cot cpa cpb cpc cpe cpo cpp cpr cpt cra crb crc cre cro crp crr crt cta ctb ctc cte cto ctp ctr ctt eaa eab eac eae eao eap ear eat eba ebb ebc ebe ebo ebp ebr ebt ec- eca ecb ecc ece eco ecr ect eea eeb eec eee eeo eep eer eet eo- eoa eob eoc eoe eoo eop eor eot ep- epa epb epc epe epo epp epr ept era erb erc ere ero erp err ert eta etb etc ete eto etp etr ett oaa oab oac oae oao oap oar oat ob- oba obb obc obe obo obp obr obt oc- oca ocb occ oco ocp ocr oct oea oeb oec oee oeo oep oer oet oo- ooa oob ooc ooo oop oor oot op- opa opb opc ope opo opp opr opt or- ora orb orc ore oro orp orr ort ot- ota otb otc ote oto otp otr ott p-p paa pab pac pae pao pap par pat pba pbb pbc pbe pbo pbp pbr pbt pca pcb pcc pce pco pcp pcr pct pea peb pec pee peo pep per pet poa pob poc poe poo pop por pot ppa ppb ppc ppe ppo ppp ppr ppt pra prb prc pre pro prp prr prt pt- pta ptb ptc pte pto ptp ptr ptt ra- raa rab rac rae rao rap rar rat rba rbb rbc rbe rbo rbp rbr rbt rca rcb rcc rce rco rcp rcr rct re- rea reb rec ree reo rep rer ret roa rob roc roe roo rop ror rot rpa rpb rpc rpe rpo rpp rpr rpt rra rrb rrc rrp rrr rrt rta rtb rtc rte rto rtp rtr rtt taa tab tac tae tao tap tar tat tba tbb tbc tbe tbo tbp tbr tbt tca tcb tcc tce tco tcp tcr tct te- tea teb tec tee teo tep ter tet to- toa tob toc toe too top tor tot tpa tpb tpc tpe tpo tpp tpr tpt tra trb trc tre tro trp trr trt tta ttb ttc tte tto ttp ttr ttt