-er a-a a-b a-c a-t aaa aab aac aae aao aap aar aas aat ab- aba abb abc abe abo abp abr abs abt ac- aca acb acc ace aco acp acr acs act aea aeb aec aee aeo aep aer aes aet aoa aob aoc aoe aoo aop aor aos aot ap- apa apb apc ape apo app apr aps apt ar- ara arb arc are aro arp arr ars art as- asa asb asc ase aso asp asr ass ast at- ata atb atc ate ato atp atr ats att b-p baa bab bac bae bao bap bar bas bat bba bbb bbc bbe bbo bbp bbr bbs bbt bca bcb bcc bce bco bcp bcr bcs bct be- bea beb bec bee beo bep ber bes bet boa bob boc boe boo bop bor bos bot bpa bpb bpc bpe bpo bpp bpr bps bpt bra brb bre bro brp brr brs brt bsa bsb bsc bse bso bsp bsr bss bst bta btb btc bte bto btp btr bts btt c-- caa cab cac cae cao cap car cas cat cba cbb cbc cbe cbo cbp cbr cbs cbt cca ccb ccc cce cco ccp ccr ccs cct ce- cea ceb cec cee ceo cep cer ces cet co- coa cob coc coe coo cop cor cos cot cpa cpb cpc cpe cpo cpp cpr cps cpt cra crb crc cre cro crp crr crs crt csa csb csc cse cso csp csr css cst cta ctb ctc cte cto ctp ctr cts ctt eaa eab eac eae eao eap ear eas eat eba ebb ebc ebe ebo ebp ebr ebs ebt ec- eca ecb ecc ece eco ecr ecs ect eea eeb eec eee eeo eep eer ees eet eo- eoa eob eoc eoe eoo eop eor eos eot ep- epa epb epc epe epo epp epr eps ept era erb erc ere ero erp err ers ert es- esa esb esc ese eso esp esr ess est eta etb etc ete eto etp etr ets ett oaa oab oac oae oao oap oar oas oat ob- oba obb obc obe obo obp obr obs obt oc- oca ocb occ oco ocp ocr ocs oct oea oeb oec oee oeo oep oer oes oet oo- ooa oob ooc ooo oop oor oos oot op- opa opb opc ope opo opp opr ops opt or- ora orb orc ore oro orp orr ors ort os- osa osb osc ose oso osp osr oss ost ot- ota otb otc ote oto otp otr ots ott p-p paa pab pac pae pao pap par pas pat pba pbb pbc pbe pbo pbp pbr pbs pbt pca pcb pcc pce pco pcp pcr pcs pct pea peb pec pee peo pep per pes pet poa pob poc poe poo pop por pos pot ppa ppb ppc ppe ppo ppp ppr pps ppt pra prb prc pre pro prp prr prs prt ps- psa psb psc pse pso psp psr pss pst pt- pta ptb ptc pte pto ptp ptr pts ptt ra- raa rab rac rae rao rap rar ras rat rba rbb rbc rbe rbo rbp rbr rbs rbt rca rcb rcc rce rco rcp rcr rcs rct re- rea reb rec ree reo rep rer res ret roa rob roc roe roo rop ror ros rot rpa rpb rpc rpe rpo rpp rpr rps rpt rra rrb rrc rrp rrr rrs rrt rsa rsb rsc rse rso rsp rsr rss rst rta rtb rtc rte rto rtp rtr rts rtt saa sab sac sae sao sap sar sas sat sba sbb sbc sbe sbo sbp sbr sbs sbt sca scb scc sce sco scp scr scs sct se- sea seb sec see seo sep ser ses set soa sob soc soe soo sop sor sos sot spa spb spc spe spo spp spr sps spt sr- sra srb src sre sro srp srr srs srt ss- ssa ssb ssc sse sso ssp ssr sss sst sta stb stc ste sto stp str sts stt taa tab tac tae tao tap tar tas tat tba tbb tbc tbe tbo tbp tbr tbs tbt tca tcb tcc tce tco tcp tcr tcs tct te- tea teb tec tee teo tep ter tes tet to- toa tob toc toe too top tor tos tot tpa tpb tpc tpe tpo tpp tpr tps tpt tra trb trc tre tro trp trr trs trt tsa tsb tsc tse tso tsp tsr tss tst tta ttb ttc tte tto ttp ttr tts ttt