a-a aaa aao aar aas aax aoa aoo aor aos aox ar- ara aro arr ars arx as- asa aso asr ass asx ax- axa axo axr axs axx oaa oao oar oas oax oo- ooa ooo oor oos oox or- ora oro orr ors orx os- osa oso osr oss osx ox- oxa oxo oxx ra- raa rao rar ras rax roa roo ror ros rox rra rrr rrs rsa rso rsr rss rsx rxr rxs saa sao sar sas sax soa soo sor sos sox sr- sra sro srr srs srx ss- ssa sso ssr sss ssx sxs xaa xar xas xoa xoo xor xos xox xrx xsa xss xxo xxx