b-u bbb bbi bbr bbt bbu bi- bib bii bir bit biu biv brb bri brr brt bru brv btb bti btr btt btu btv bub bui bur but buu bvb bvi bvr bvt bvu bvv i-v ibb ibi ibr ibt ibu ibv iib iii iir iit iiu ir- irb iri irr irt iru irv itb iti itt itu itv iu- iub iui iur iut ivb ivi ivr ivt ivu ivv rbb rbi rbr rbt rbu rib rii rir rit riv rrb rri rrr rrt rru rtb rti rtr rtt rtu rtv rub rui rur rut ruu ruv rvb rvi rvr rvt rvu rvv tbb tbi tbr tbt tbu tbv tib tii tir tit tiu tiv trb tri trr trt tru trv ttb tti ttr ttt ttu ttv tub tui tur tut tuu tuv tvb tvi tvr tvt tvu ubb ubi ubr ubt ubu ubv uib uii uir uit uiu ur- urb uri urr urt uru utb uti utr utt utu utv uur uut uuu uvb uvu uvv vbi vbr vbv vi- vib vii vir vit viu viv vrb vri vrr vrt vru vtb vti vtr vtt vtu vtv vur vut vuv vvb vvi vvr vvt vvv