-er bbb bbe bbi bbk bbn bbo bbr bbt bbx be- beb bee bei bek ben beo ber bet bex bi- bib bie bii bik bin bio bir bit bix bkb bke bkk bkn bko bkr bkt bkx bnb bne bni bnk bnn bno bnr bnt bnx bob boe boi bok bon boo bor bot box brb bre bri brk brn bro brr brt brx btb bte bti btk btn bto btr btt btx bxb bxi bxn bxo bxx ebb ebe ebi ebk ebn ebo ebr ebt ebx eeb eee eek een eeo eer eet eex eib eie eii eik ein eio eir eit eix ekb eke eki eko ekr ekt en- enb ene eni enk enn eno enr ent eo- eob eoe eoi eok eon eoo eor eot erb ere eri erk ern ero err ert etb ete eti etk etn eto etr ett etx ex- exe exi exo exr ext exx ibb ibe ibi ibk ibn ibo ibr ibt ibx ie- iee iei iek ien ier iet iex iib iie iii iin iio iir iit iix ikb ike iki ikk iko ikr ikt ikx in- inb ine ini ink inn ino inr int inx io- iob ioe ioi ion ioo ior iot ir- irb ire iri irk irn iro irr irt irx itb ite iti itk itn ito itt itx ixe ixi ixn k-t kbb kbe kbi kbk kbn kbo kbr kbx ke- keb kee kei kek ken keo ker ket kex kib kie kii kik kin kio kir kit kix kkb kke kki kkk kkn kkr kkt kn- kne kni knk knn kno knr knt knx kob koe koi kok kon koo kor kot kri krk krn kro krr krt ktb kte ktk ktn kto ktr ktt kxo n-i nbb nbe nbi nbk nbn nbo nbr nbt nbx ne- neb nee nei nek nen neo ner net nex nib nie nii nik nin nio nir nit nix nke nki nkk nkn nko nkr nkt nnb nne nni nnk nnn nno nnt no- nob noe noi nok non noo nor not nox nrb nre nri nrk nrn nro nrr nrt nrx ntb nte nti ntk ntn nto ntr ntt ntx nxt o-i ob- obb obe obi obk obn obo obr obt obx oeb oee oei oen oeo oer oet oex oib oie oii oik oin oio oir oit okb oke oki okk oko okr on- onb one oni onk onn ono onr ont onx oo- oob ooi ook oon ooo oor oot oox or- orb ore ori ork orn oro orr ort orx ot- otb ote oti otk otn oto otr ott ox- oxb oxi oxn oxo oxt oxx rbb rbe rbi rbk rbn rbo rbr rbt rbx re- reb ree rei rek ren reo rer ret rex rib rie rii rik rin rio rir rit rix rkb rke rkk rko rkt rnb rni rnn rno rnr rnt rob roe roi rok ron roo ror rot rox rrb rri rrk rrn rrr rrt rtb rte rti rtk rtn rto rtr rtt rtx rxr t-x tbb tbe tbi tbk tbn tbo tbr tbt te- teb tee tei tek ten teo ter tet tex tib tie tii tik tin tio tir tit tix tkb tke tkk tko tkr tkt tnb tne tni tnk tnn tno tnr tnt tnx to- tob toe toi tok ton too tor tot tox trb tre tri trk trn tro trr trt trx ttb tte tti ttk ttn tto ttr ttt ttx txe txi txk txn txt xbe xbr xbx xee xen xer xet xex xie xii xin xio xit xix xkb xke xnk xno xoi xok xon xoo xor xot xox xrt xrx xti xtr xtx xxi xxo xxx