-er bbb bbe bbi bbk bbo bbr be- beb bee bei bek beo ber bez bi- bib bie bii bik bio bir biz bkb bke bkk bko bkr bob boe boi bok boo bor boz brb bre bri brk bro brr brz bze bzo bzr bzz ebb ebe ebi ebk ebo ebr eeb eee eek eeo eer eib eie eii eik eio eir ekb eke eki eko ekr eo- eob eoe eoi eok eoo eor erb ere eri erk ero err erz eze ezo ezr ezz ibb ibe ibi ibk ibo ibr ibz ie- iee iei iek ier iib iie iii iio iir ikb ike iki ikk iko ikr io- iob ioe ioi ioo ior ir- irb ire iri irk iro irr ize izi izo izz k-z kbb kbe kbi kbk kbo kbr kbz ke- keb kee kei kek keo ker kez kib kie kii kik kio kir kiz kkb kke kki kkk kkr kob koe koi kok koo kor koz kri krk kro krr kzo o-i ob- obb obe obi obk obo obr oeb oee oei oeo oer oib oie oii oik oio oir oiz okb oke oki okk oko okr oo- oob ooi ook ooo oor or- orb ore ori ork oro orr orz oze ozo ozz rbb rbe rbi rbk rbo rbr re- reb ree rei rek reo rer rez rib rie rii rik rio rir riz rkb rke rkk rko rkz rob roe roi rok roo ror roz rrb rri rrk rrr rzb rze rzo zbb zbr zeb zee zek zeo zer zez zib zie zik zio zir ziz zo- zob zoe zoi zok zoo zor zro zzr zzz