b-u bbb bbi bbr bbs bbu bi- bib bii bir bis biu biv brb bri brr brs bru brv bsb bsi bsr bss bsu bsv bub bui bur bus buu bvb bvi bvr bvs bvu bvv i-v ibb ibi ibr ibs ibu ibv iib iii iir iis iiu ir- irb iri irr irs iru irv is- isb isi isr iss isu isv iu- iub iui iur ius ivb ivi ivr ivs ivu ivv rbb rbi rbr rbs rbu rib rii rir ris riv rrb rri rrr rrs rru rsb rsi rsr rss rsu rsv rub rui rur rus ruu ruv rvb rvi rvr rvs rvu rvv sbb sbi sbr sbs sbu sbv sib sii sir sis siu siv sr- srb sri srr srs srv ss- ssb ssi ssr sss ssu ssv sub sui sur sus suu suv svb svi svr svs svu svv ubb ubi ubr ubs ubu ubv uib uii uir uis uiu ur- urb uri urr urs uru usb usi usr uss usu usv uur uus uuu uvb uvs uvu uvv vbi vbr vbs vbv vi- vib vii vir vis viu viv vrb vri vrr vrs vru vsb vsi vsr vss vsu vsv vur vus vuv vvb vvi vvr vvs vvv