-er a-a a-b a-t aaa aab aae aag aan aao aar aat ab- aba abb abe abg abn abo abr abt aea aeb aee aeg aen aeo aer aet ag- aga agb age agg agn ago agr agt an- ana anb ane ang ann ano anr ant aoa aob aoe aog aon aoo aor aot ar- ara arb are arg arn aro arr art at- ata atb ate atg atn ato atr att baa bab bae bag ban bao bar bat bba bbb bbe bbg bbn bbo bbr bbt be- bea beb bee beg ben beo ber bet bga bgb bge bgg bgn bgo bgr bgt bna bnb bne bng bnn bno bnr bnt boa bob boe bog bon boo bor bot bra brb bre brg brn bro brr brt bta btb bte btg btn bto btr btt eaa eab eae eag ean eao ear eat eba ebb ebe ebg ebn ebo ebr ebt eea eeb eee eeg een eeo eer eet ega egb ege egg egn ego egr egt en- ena enb ene eng enn eno enr ent eo- eoa eob eoe eog eon eoo eor eot era erb ere erg ern ero err ert eta etb ete etg etn eto etr ett gaa gab gae gag gan gao gar gat gba gbe gbg gbn gbo gbr gbt ge- gea geb gee geg gen geo ger get gga ggb ggg ggn ggo ggr ggt gna gnb gne gnn gno gnr gnt goa gob goe gog gon goo gor got gra grb gre grg grn gro grr grt gta gtb gte gtg gtn gto gtr gtt naa nab nae nag nan nao nar nat nba nbb nbe nbg nbn nbo nbr nbt ne- nea neb nee neg nen neo ner net nga ngb nge ngg ngn ngo ngt nna nnb nne nng nnn nno nnt no- noa nob noe nog non noo nor not nra nrb nre nrg nrn nro nrr nrt nta ntb nte ntg ntn nto ntr ntt oaa oab oae oag oan oao oar oat ob- oba obb obe obg obn obo obr obt oea oeb oee oeg oen oeo oer oet oga oge ogg ogn ogo ogt on- ona onb one ong onn ono onr ont oo- ooa oob oog oon ooo oor oot or- ora orb ore org orn oro orr ort ot- ota otb ote otg otn oto otr ott ra- raa rab rae rag ran rao rar rat rba rbb rbe rbg rbn rbo rbr rbt re- rea reb ree reg ren reo rer ret rga rgb rge rgg rgn rgo rgr rgt rna rnb rng rnn rno rnr rnt roa rob roe rog ron roo ror rot rra rrb rrg rrn rrr rrt rta rtb rte rtg rtn rto rtr rtt taa tab tae tag tan tao tar tat tba tbb tbe tbg tbn tbo tbr tbt te- tea teb tee teg ten teo ter tet tga tgb tge tgg tgn tgo tgr tgt tna tnb tne tng tnn tno tnr tnt to- toa tob toe tog ton too tor tot tra trb tre trg trn tro trr trt tta ttb tte ttg ttn tto ttr ttt