sers sesc sese seso sess sfcc sfco sfcs sfer sffc sflc sfls sfor sfos sfpc sfrc sfro sfss slcc slee slep sler sles sllp sloc sloe sloo slop slos slpp slps slrc slre slrp slrs slsc soce socl soco socr socs soec soel soeo soep soes sofo sole solf soll solo solp solr sols soof sool soop soor soos sope sopo sopp sops sore soro sorr sors sose soso soss spcc spco spcs spec spee spef spel sper spes spfc spfs splc sple splo splp splr spls spoc spoo spop spor spos sppf spps spro sprs spse spso spsp spss srcc srec sreo sres srfc sros srpc srps srsp sscc ssce sscp sscs ssec ssee ssep sses ssfc ssfl ssfp sslc ssle sslp ssoc ssop sspc sspe sspf sspl sspo ssps ssrc ssrl ssrs sssc sssf ssss