-er a-a a-b a-i a-t aaa aab aae aag aai aan aao aar aat ab- aba abb abe abg abi abn abo abr abt aea aeb aee aeg aei aen aeo aer aet ag- aga agb age agg agi agn ago agr agt ai- aia aib aie aig aii ain aio air ait an- ana anb ane ang ani ann ano anr ant aoa aob aoe aog aoi aon aoo aor aot ar- ara arb are arg ari arn aro arr art at- ata atb ate atg ati atn ato atr att baa bab bae bag bai ban bao bar bat bba bbb bbe bbg bbi bbn bbo bbr bbt be- bea beb bee beg bei ben beo ber bet bga bgb bge bgg bgi bgn bgo bgr bgt bi- bia bib bie big bii bin bio bir bit bna bnb bne bng bni bnn bno bnr bnt boa bob boe bog boi bon boo bor bot bra brb bre brg bri brn bro brr brt bta btb bte btg bti btn bto btr btt eaa eab eae eag eai ean eao ear eat eba ebb ebe ebg ebi ebn ebo ebr ebt eea eeb eee eeg een eeo eer eet ega egb ege egg egi egn ego egr egt eia eib eie eig eii ein eio eir eit en- ena enb ene eng eni enn eno enr ent eo- eoa eob eoe eog eoi eon eoo eor eot era erb ere erg eri ern ero err ert eta etb ete etg eti etn eto etr ett gaa gab gae gag gai gan gao gar gat gba gbe gbg gbi gbn gbo gbr gbt ge- gea geb gee geg gei gen geo ger get gga ggb ggg ggi ggn ggo ggr ggt gia gib gie gig gii gin gio gir git gna gnb gne gni gnn gno gnr gnt goa gob goe gog goi gon goo gor got gra grb gre grg gri grn gro grr grt gta gtb gte gtg gti gtn gto gtr gtt ia- iaa iab iae iag iai ian iao iar iat iba ibb ibe ibg ibi ibn ibo ibr ibt ie- iea iee ieg iei ien ier iet iga igb ige igg igi ign igo igr igt iia iib iie iii iin iio iir iit in- ina inb ine ing ini inn ino inr int io- ioa iob ioe iog ioi ion ioo ior iot ir- ira irb ire irg iri irn iro irr irt ita itb ite itg iti itn ito itt n-i naa nab nae nag nai nan nao nar nat nba nbb nbe nbg nbi nbn nbo nbr nbt ne- nea neb nee neg nei nen neo ner net nga ngb nge ngg ngi ngn ngo ngt nia nib nie nig nii nin nio nir nit nna nnb nne nng nni nnn nno nnt no- noa nob noe nog noi non noo nor not nra nrb nre nrg nri nrn nro nrr nrt nta ntb nte ntg nti ntn nto ntr ntt o-i oaa oab oae oag oai oan oao oar oat ob- oba obb obe obg obi obn obo obr obt oea oeb oee oeg oei oen oeo oer oet oga oge ogg ogi ogn ogo ogt oia oib oie oii oin oio oir oit on- ona onb one ong oni onn ono onr ont oo- ooa oob oog ooi oon ooo oor oot or- ora orb ore org ori orn oro orr ort ot- ota otb ote otg oti otn oto otr ott ra- raa rab rae rag rai ran rao rar rat rba rbb rbe rbg rbi rbn rbo rbr rbt re- rea reb ree reg rei ren reo rer ret rga rgb rge rgg rgi rgn rgo rgr rgt ria rib rie rig rii rin rio rir rit rna rnb rng rni rnn rno rnr rnt roa rob roe rog roi ron roo ror rot rra rrb rrg rri rrn rrr rrt rta rtb rte rtg rti rtn rto rtr rtt taa tab tae tag tai tan tao tar tat tba tbb tbe tbg tbi tbn tbo tbr tbt te- tea teb tee teg tei ten teo ter tet tga tgb tge tgg tgi tgn tgo tgr tgt tia tib tie tig tii tin tio tir tit tna tnb tne tng tni tnn tno tnr tnt to- toa tob toe tog toi ton too tor tot tra trb tre trg tri trn tro trr trt tta ttb tte ttg tti ttn tto ttr ttt