bbb bbn bbo bbs bnb bnn bno bns bnz bob bon boo bos boz bsb bsn bso bss bzn bzo bzs bzz nbb nbn nbo nbs nnb nnn nno nns nnz no- nob non noo nos noz nsb nsn nso nss nsz nzb nzo nzs nzz ob- obb obn obo obs on- onb onn ono ons oo- oob oon ooo oos os- osb osn oso oss ozo ozs ozz sbb sbn sbo sbs snb snn sno sns sob son soo sos soz ss- ssb ssn sso sss ssz zbb zbs znn zno zns zo- zob zon zoo zos zsz zzs zzz