-ol bbb bbi bbl bbo bbs bbt bi- bib bii bil bio bis bit blb bli bll blo bls blt bob boi bol boo bos bot bsb bsi bsl bso bss bst btb bti btl bto bts btt ibb ibi ibl ibo ibs ibt iib iii iil iio iis iit il- ilb ili ill ilo ils ilt io- iob ioi iol ioo ios iot is- isb isi isl iso iss ist itb iti itl ito its itt lbb lbi lbl lbo lbs lbt lib lii lil lio lis lit llb lli lll llo lls llt lob loi lol loo los lot lsb lsi lsl lso lss lst ltb lti ltl lto lts ltt o-i ob- obb obi obl obo obs obt oib oii oil oio ois oit olb oli oll olo ols olt oo- oob ooi ool ooo oos oot os- osb osi osl oso oss ost ot- otb oti otl oto ots ott sbb sbi sbl sbo sbs sbt sib sii sil sio sis sit slb sli sll slo sls slt sob soi sol soo sos sot ss- ssb ssi ssl sso sss sst stb sti stl sto sts stt tbb tbi tbl tbo tbs tbt tib tii til tio tis tit tli tll tlo tls tlt to- tob toi tol too tos tot tsb tsi tsl tso tss tst ttb tti ttl tto tts ttt