a-a a-c aaa aac aan aao aap aas ac- aca acc acn aco acp acs an- ana anc ann ano anp ans aoa aoc aon aoo aop aos ap- apa apc apn apo app aps as- asa asc asn aso asp ass c-- caa cac can cao cap cas cca ccc ccn cco ccp ccs cn- cna cnc cnn cno cnp cns co- coa coc con coo cop cos cpa cpc cpn cpo cpp cps csa csc csn cso csp css naa nac nan nao nap nas nca ncc ncn nco ncp ncs nna nnc nnn nno nnp nns no- noa noc non noo nop nos npa npc npn npo npp nps nsa nsc nsn nso nsp nss oaa oac oan oao oap oas oc- oca occ ocn oco ocp ocs on- ona onc onn ono onp ons oo- ooa ooc oon ooo oop oos op- opa opc opn opo opp ops os- osa osc osn oso osp oss p-p paa pac pan pao pap pas pca pcc pcn pco pcp pcs pn- pna pnc pnn pno pnp pns poa poc pon poo pop pos ppa ppc ppn ppo ppp pps ps- psa psc psn pso psp pss saa sac san sao sap sas sca scc scn sco scp scs sna snc snn sno snp sns soa soc son soo sop sos spa spc spn spo spp sps ss- ssa ssc ssn sso ssp sss