a-a aaa aan aao aap aas an- ana ann ano anp ans aoa aon aoo aop aos ap- apa apn apo app aps as- asa asn aso asp ass naa nan nao nap nas nna nnn nno nnp nns no- noa non noo nop nos npa npn npo npp nps nsa nsn nso nsp nss oaa oan oao oap oas on- ona onn ono onp ons oo- ooa oon ooo oop oos op- opa opn opo opp ops os- osa osn oso osp oss p-p paa pan pao pap pas pn- pna pnn pno pnp pns poa pon poo pop pos ppa ppn ppo ppp pps ps- psa psn pso psp pss saa san sao sap sas sna snn sno snp sns soa son soo sop sos spa spn spo spp sps ss- ssa ssn sso ssp sss