sfb sfe sff sfk sfl sfm sfn sfo sfr sfs sk- skb ske skf skk skl skm sko skr sks sky slb sle slf slk sll slm sln slo slr sls sly smb sme smf smk sml smm smn smo smr sms smy snb sne snf snk snl snm snn sno snr sns sny sob soe sof sok sol som son soo sor sos soy sr- srb sre srf srk srl srm srn sro srr srs sry ss- ssb sse ssf ssk ssl ssm ssn sso ssr sss sy- syb sye syk syl sym syn syr sys ybe ybf ybl ybm ybr ybs yby yeb yee yef yek yel yem yen yeo yer yes yey yfe yff yfm yfr yfs ykk ykm ykn yle ylk yll ylm ylr yls yly yme yml ymm ymo yms yne ynk ynn yns yny yob yoe yof yok yol yom yon yoo yor yos yoy yre yrf yrn yro yrs ysb yse ysk ysl ysm yso ysr yss ysy yyb yye yyf yys yyy