a-a a-c aaa aac aan aar aas ac- aca acc acn acr acs an- ana anc ann anr ans ar- ara arc arn arr ars as- asa asc asn asr ass c-- caa cac can car cas cca ccc ccn ccr ccs cn- cna cnc cnn cnr cns cra crc crn crr crs csa csc csn csr css naa nac nan nar nas nca ncc ncn ncr ncs nna nnc nnn nns nra nrc nrn nrr nrs nsa nsc nsn nsr nss ra- raa rac ran rar ras rca rcc rcn rcr rcs rna rnc rnn rnr rns rra rrc rrn rrr rrs rsa rsc rsn rsr rss saa sac san sar sas sca scc scn scr scs sna snc snn snr sns sr- sra src srn srr srs ss- ssa ssc ssn ssr sss