-ic bbb bbc bbi bbo bbr bbs bcb bcc bci bco bcr bcs bi- bib bic bii bio bir bis bob boc boi boo bor bos brb bri bro brr brs bsb bsc bsi bso bsr bss c-- cbb cbc cbi cbo cbr cbs ccb ccc cci cco ccr ccs ci- cib cic cii cio cir cis co- cob coc coi coo cor cos crb crc cri cro crr crs csb csc csi cso csr css ibb ibc ibi ibo ibr ibs icb icc ici ico icr ics iib iic iii iio iir iis io- iob ioc ioi ioo ior ios ir- irb irc iri iro irr irs is- isb isc isi iso isr iss o-i ob- obb obc obi obo obr obs oc- ocb occ oci oco ocr ocs oib oic oii oio oir ois oo- oob ooc ooi ooo oor oos or- orb orc ori oro orr ors os- osb osc osi oso osr oss rbb rbc rbi rbo rbr rbs rcb rcc rci rco rcr rcs rib ric rii rio rir ris rob roc roi roo ror ros rrb rrc rri rrr rrs rsb rsc rsi rso rsr rss sbb sbc sbi sbo sbr sbs scb scc sci sco scr scs sib sic sii sio sir sis sob soc soi soo sor sos sr- srb src sri sro srr srs ss- ssb ssc ssi sso ssr sss