a-a a-c aaa aac aan aao aas aax ac- aca acc acn aco acs acx an- ana anc ann ano ans anx aoa aoc aon aoo aos aox as- asa asc asn aso ass asx ax- axa axn axo axs axx c-- caa cac can cao cas cax cca ccc ccn cco ccs ccx cn- cna cnc cnn cno cns cnx co- coa coc con coo cos cox csa csc csn cso css csx cxc cxo cxs cxx naa nac nan nao nas nax nca ncc ncn nco ncs ncx nna nnc nnn nno nns no- noa noc non noo nos nox nsa nsc nsn nso nss nsx nxc oaa oac oan oao oas oax oc- oca occ ocn oco ocs ocx on- ona onc onn ono ons onx oo- ooa ooc oon ooo oos oox os- osa osc osn oso oss osx ox- oxa oxc oxn oxo oxx saa sac san sao sas sax sca scc scn sco scs scx sna snc snn sno sns soa soc son soo sos sox ss- ssa ssc ssn sso sss ssx sxc sxn sxs xaa xac xan xas xcx xna xnc xno xns xoa xoc xon xoo xos xox xsa xsc xss xxo xxx