bbb bbi bbk bbo bbr bi- bib bii bik bio bir bkb bkk bko bkr bob boi bok boo bor brb bri brk bro brr ibb ibi ibk ibo ibr iib iii iio iir ikb iki ikk iko ikr io- iob ioi ioo ior ir- irb iri irk iro irr kbb kbi kbk kbo kbr kib kii kik kio kir kkb kki kkk kkr kob koi kok koo kor kri krk kro krr o-i ob- obb obi obk obo obr oib oii oik oio oir okb oki okk oko okr oo- oob ooi ook ooo oor or- orb ori ork oro orr rbb rbi rbk rbo rbr rib rii rik rio rir rkb rkk rko rob roi rok roo ror rrb rri rrk rrr