rir ris rit rkc rke rkk rko rkp rks rkt rlc rld rle rli rll rlo rlp rlr rls rlt roc rod roe roi rok rol roo rop ror ros rot rpc rpd rpe rpi rpk rpl rpo rpp rpr rps rpt rrc rrd rri rrk rrl rrp rrr rrs rrt rsc rsd rse rsi rsk rsl rso rsp rsr rss rst rtc rtd rte rti rtk rtl rto rtp rtr rts rtt scc scd sce sci sck scl sco scp scr scs sct sdc sdd sde sdi sdk sdl sdo sdp sdr sds sdt se- sec sed see sei sek sel seo sep ser ses set sic sid sie sii sik sil sio sip sir sis sit sk- skc skd ske ski skk skl sko skp skr sks skt slc sld sle sli slk sll slo slp slr sls slt soc sod soe soi sok sol soo sop sor sos sot spc spd spe spi spk spl spo spp spr sps spt sr- src srd sre sri srk srl sro srp srr srs srt ss- ssc ssd sse ssi ssk ssl sso ssp ssr sss sst stc std ste sti stk stl sto stp str sts stt tcc tcd tce tci tck tcl tco tcp tcr tcs tct tdc tdd tde tdi tdk tdl tdo tdp tdr tds tdt te- tec ted tee tei tek tel teo tep ter tes tet tic tid tie tii tik til tio tip tir tis tit tkc tke tkk tkl tko tkp tkr tks tkt tlc tld tle tli tlk tll tlo tlp tlr tls tlt to- toc tod toe toi tok tol too top tor tos tot tpc tpd tpe tpi tpk tpl tpo tpp tpr tps tpt trc trd tre tri trk trl tro trp trr trs trt tsc tsd tse tsi tsk tsl tso tsp tsr tss tst ttc ttd tte tti ttk ttl tto ttp ttr tts ttt