a-a a-c aaa aac aad aak aas ac- aca acc acd ack acs ad- ada adc add adk ads aka akc akd akk aks as- asa asc asd ask ass c-- caa cac cad cak cas cca ccc ccd cck ccs cda cdc cdd cdk cds cka ckc ckd cks csa csc csd csk css daa dac dad dak das dca dcc dcd dck dcs dda ddc ddd ddk dds dka dkc dkk dks dsa dsc dsd dsk dss ka- kaa kac kad kak kas kca kcc kcd kck kcs kda kdc kdk kds kkc kkk kks ksa ksc ksd ksk kss saa sac sad sak sas sca scc scd sck scs sda sdc sdd sdk sds sk- ska skc skd skk sks ss- ssa ssc ssd ssk sss