bbb bbi bbm bbr bbs bbx bi- bib bii bim bir bis bix bmb bmi bmm bmr bms bmx brb bri brm brr brs brx bsb bsi bsm bsr bss bsx bxb bxi bxm bxx ibb ibi ibm ibr ibs ibx iib iii iim iir iis iix im- imb imi imm ims imx ir- irb iri irm irr irs irx is- isb isi ism isr iss ixi m-r mbb mbi mbm mbr mbs mbx mi- mib mii mim mir mis mix mmb mmi mmm mmr mms mmx mrb mri mrm mrr mrs mrx msb msi msm msr mss msx mxi mxr mxs rbb rbi rbm rbr rbs rbx rib rii rim rir ris rix rmb rmi rmm rmr rms rmx rrb rri rrm rrr rrs rsb rsi rsm rsr rss rsx rxr rxs sbb sbi sbm sbr sbs sbx sib sii sim sir sis six smb smi smm smr sms smx sr- srb sri srm srr srs srx ss- ssb ssi ssm ssr sss ssx sxi sxm sxs xbr xbx xii xis xix xmi xmm xmr xms xmx xrx xsb xsi xsm xss xxi xxx