bbb bbi bbn bbo bbs bbt bi- bib bii bin bio bis bit bnb bni bnn bno bns bnt bob boi bon boo bos bot bsb bsi bsn bso bss bst btb bti btn bto bts btt ibb ibi ibn ibo ibs ibt iib iii iin iio iis iit in- inb ini inn ino ins int io- iob ioi ion ioo ios iot is- isb isi isn iso iss ist itb iti itn ito its itt n-i nbb nbi nbn nbo nbs nbt nib nii nin nio nis nit nnb nni nnn nno nns nnt no- nob noi non noo nos not nsb nsi nsn nso nss nst ntb nti ntn nto nts ntt o-i ob- obb obi obn obo obs obt oib oii oin oio ois oit on- onb oni onn ono ons ont oo- oob ooi oon ooo oos oot os- osb osi osn oso oss ost ot- otb oti otn oto ots ott sbb sbi sbn sbo sbs sbt sib sii sin sio sis sit snb sni snn sno sns snt sob soi son soo sos sot ss- ssb ssi ssn sso sss sst stb sti stn sto sts stt tbb tbi tbn tbo tbs tbt tib tii tin tio tis tit tnb tni tnn tno tns tnt to- tob toi ton too tos tot tsb tsi tsn tso tss tst ttb tti ttn tto tts ttt