bbb bbi bbo bbr bbs bi- bib bii bio bir bis biv bob boi boo bor bos bov brb bri bro brr brs brv bsb bsi bso bsr bss bsv bvb bvi bvo bvr bvs bvv i-v ibb ibi ibo ibr ibs ibv iib iii iio iir iis io- iob ioi ioo ior ios iov ir- irb iri iro irr irs irv is- isb isi iso isr iss isv ivb ivi ivo ivr ivs ivv o-i ob- obb obi obo obr obs obv oib oii oio oir ois oiv oo- oob ooi ooo oor oos oov or- orb ori oro orr ors orv os- osb osi oso osr oss osv ov- ovb ovi ovo ovs ovv rbb rbi rbo rbr rbs rib rii rio rir ris riv rob roi roo ror ros rov rrb rri rrr rrs rsb rsi rso rsr rss rsv rvb rvi rvo rvr rvs rvv sbb sbi sbo sbr sbs sbv sib sii sio sir sis siv sob soi soo sor sos sov sr- srb sri sro srr srs srv ss- ssb ssi sso ssr sss ssv svb svi svo svr svs svv vbi vbo vbr vbs vbv vi- vib vii vio vir vis viv vob voi voo vor vos vov vrb vri vrr vrs vsb vsi vso vsr vss vsv vvb vvi vvo vvr vvs vvv