-er a-a a-b a-c a-t aaa aab aac aae aag aan aao aar aat ab- aba abb abc abe abg abn abo abr abt ac- aca acb acc ace acg acn aco acr act aea aeb aec aee aeg aen aeo aer aet ag- aga agb agc age agg agn ago agr agt an- ana anb anc ane ang ann ano anr ant aoa aob aoc aoe aog aon aoo aor aot ar- ara arb arc are arg arn aro arr art at- ata atb atc ate atg atn ato atr att baa bab bac bae bag ban bao bar bat bba bbb bbc bbe bbg bbn bbo bbr bbt bca bcb bcc bce bcg bcn bco bcr bct be- bea beb bec bee beg ben beo ber bet bga bgb bgc bge bgg bgn bgo bgr bgt bna bnb bnc bne bng bnn bno bnr bnt boa bob boc boe bog bon boo bor bot bra brb bre brg brn bro brr brt bta btb btc bte btg btn bto btr btt c-- caa cab cac cae cag can cao car cat cba cbb cbc cbe cbg cbn cbo cbr cbt cca ccb ccc cce ccg ccn cco ccr cct ce- cea ceb cec cee ceg cen ceo cer cet cga cgb cgc cge cgg cgn cgo cgr cgt cn- cna cnb cnc cne cng cnn cno cnr cnt co- coa cob coc coe cog con coo cor cot cra crb crc cre crg crn cro crr crt cta ctb ctc cte ctg ctn cto ctr ctt eaa eab eac eae eag ean eao ear eat eba ebb ebc ebe ebg ebn ebo ebr ebt ec- eca ecb ecc ece ecg ecn eco ecr ect eea eeb eec eee eeg een eeo eer eet ega egb egc ege egg egn ego egr egt en- ena enb enc ene eng enn eno enr ent eo- eoa eob eoc eoe eog eon eoo eor eot era erb erc ere erg ern ero err ert eta etb etc ete etg etn eto etr ett gaa gab gac gae gag gan gao gar gat gba gbc gbe gbg gbn gbo gbr gbt gca gcb gcc gce gcg gcn gco gcr gct ge- gea geb gec gee geg gen geo ger get gga ggb ggc ggg ggn ggo ggr ggt gna gnb gnc gne gnn gno gnr gnt goa gob goc goe gog gon goo gor got gra grb grc gre grg grn gro grr grt gta gtb gtc gte gtg gtn gto gtr gtt naa nab nac nae nag nan nao nar nat nba nbb nbc nbe nbg nbn nbo nbr nbt nca ncb ncc nce ncg ncn nco ncr nct ne- nea neb nec nee neg nen neo ner net nga ngb ngc nge ngg ngn ngo ngt nna nnb nnc nne nng nnn nno nnt no- noa nob noc noe nog non noo nor not nra nrb nrc nre nrg nrn nro nrr nrt nta ntb ntc nte ntg ntn nto ntr ntt oaa oab oac oae oag oan oao oar oat ob- oba obb obc obe obg obn obo obr obt oc- oca ocb occ ocg ocn oco ocr oct oea oeb oec oee oeg oen oeo oer oet oga ogc oge ogg ogn ogo ogt on- ona onb onc one ong onn ono onr ont oo- ooa oob ooc oog oon ooo oor oot or- ora orb orc ore org orn oro orr ort ot- ota otb otc ote otg otn oto otr ott ra- raa rab rac rae rag ran rao rar rat rba rbb rbc rbe rbg rbn rbo rbr rbt rca rcb rcc rce rcg rcn rco rcr rct re- rea reb rec ree reg ren reo rer ret rga rgb rgc rge rgg rgn rgo rgr rgt rna rnb rnc rng rnn rno rnr rnt roa rob roc roe rog ron roo ror rot rra rrb rrc rrg rrn rrr rrt rta rtb rtc rte rtg rtn rto rtr rtt taa tab tac tae tag tan tao tar tat tba tbb tbc tbe tbg tbn tbo tbr tbt tca tcb tcc tce tcg tcn tco tcr tct te- tea teb tec tee teg ten teo ter tet tga tgb tgc tge tgg tgn tgo tgr tgt tna tnb tnc tne tng tnn tno tnr tnt to- toa tob toc toe tog ton too tor tot tra trb trc tre trg trn tro trr trt tta ttb ttc tte ttg ttn tto ttr ttt