-er bbb bbe bbi bbk bbr be- beb bee bei bek ber bev bi- bib bie bii bik bir biv bkb bke bkk bkr bkv brb bre bri brk brr brv bvb bve bvi bvk bvr bvv ebb ebe ebi ebk ebr ebv eeb eee eek eer eev eib eie eii eik eir eiv ekb eke eki ekr ekv erb ere eri erk err erv evb eve evi evr evv i-v ibb ibe ibi ibk ibr ibv ie- iee iei iek ier iev iib iie iii iir ikb ike iki ikk ikr ikv ir- irb ire iri irk irr irv ivb ive ivi ivr ivv kbb kbe kbi kbk kbr ke- keb kee kei kek ker kev kib kie kii kik kir kiv kkb kke kki kkk kkr kkv kri krk krr krv kvb kvi kvk kvr kvv rbb rbe rbi rbk rbr re- reb ree rei rek rer rev rib rie rii rik rir riv rkb rke rkk rkv rrb rri rrk rrr rvb rve rvi rvr rvv v-e vbi vbk vbr vbv veb vee vei vek ver vi- vib vie vii vik vir viv vkb vrb vre vri vrk vrr vvb vvi vvr vvv