-ol b-u bbb bbl bbo bbr bbt bbu blb bll blo blr blt blu bob bol boo bor bot bou brb brl bro brr brt bru btb btl bto btr btt btu bub bul buo bur but buu lbb lbl lbo lbr lbt lbu llb lll llo llr llt llu lob lol loo lor lot lou lrb lro lrr lrt lru ltb ltl lto ltr ltt ltu lub lul luo lur lut luu ob- obb obl obo obr obt obu olb oll olo olt olu oo- oob ool ooo oor oot or- orb orl oro orr ort oru ot- otb otl oto otr ott otu ou- oul ouo our out rbb rbl rbo rbr rbt rbu rll rlo rlr rlt rlu rob rol roo ror rot rou rrb rrl rrr rrt rru rtb rtl rto rtr rtt rtu rub ruo rur rut ruu tbb tbl tbo tbr tbt tbu tll tlo tlr tlt tlu to- tob tol too tor tot tou trb trl tro trr trt tru ttb ttl tto ttr ttt ttu tub tul tuo tur tut tuu ubb ubl ubo ubr ubt ubu ulb ull ulo ulr ult ulu uob uol uoo uor uot ur- urb url uro urr urt uru utb utl uto utr utt utu uur uut uuu