-th bbb bbh bbo bbr bbt bhb bhh bho bhr bht bob boh boo bor bot brb brh bro brr brt btb bth bto btr btt hbb hbh hbo hbr hbt hhb hhh hho hhr hht hob hoh hoo hor hot hr- hrb hrh hro hrr hrt htb hth hto htr htt ob- obb obh obo obr obt ohh oho ohr oht oo- oob ooh ooo oor oot or- orb orh oro orr ort ot- otb oth oto otr ott rbb rbh rbo rbr rbt rh- rhb rhh rho rhr rht rob roh roo ror rot rrb rrh rrr rrt rtb rto rtr rtt tbb tbh tbo tbr tbt th- thb thh tho thr tht to- tob toh too tor tot trb trh tro trr trt ttb tth tto ttr ttt