rpn rpo rpp rpr rps rpx rra rrb rrh rri rrn rrp rrr rrs rsa rsb rse rsh rsi rsn rso rsp rsr rss rsx rxp rxr rxs saa sab sae sah sai san sao sap sar sas sax sba sbb sbe sbh sbi sbn sbo sbp sbr sbs sbx se- sea seb see seh sei sen seo sep ser ses sex sh- sha shb she shh shi shn sho shp shr shs sia sib sie sih sii sin sio sip sir sis six sna snb sne sni snn sno snp snr sns soa sob soe soh soi son soo sop sor sos sox spa spb spe sph spi spn spo spp spr sps spx sr- sra srb sre srh sri srn sro srp srr srs srx ss- ssa ssb sse ssh ssi ssn sso ssp ssr sss ssx sxi sxn sxs xaa xan xap xar xas xbe xbr xbx xee xen xep xer xes xex xhp xia xie xii xin xio xis xix xna xno xns xoa xoi xon xoo xop xor xos xox xpa xpb xpe xpn xpo xpp xps xrx xsa xsb xsi xsp xss xxi xxo xxp xxx