prcs pre- preb prec pree preg prep pres prgs prps prrs prsa prsc prse prss psac psap psas psbr psca pseb psec pseg psga psgr pspp pspr psps psrp pssa pssc psse raab raag raas raba rabb rabe rabs rac- raca racc race racs raec raeg raep raer raes raga rage ragg rags rapa rapc rape rapp raps rara rarb rare rars rasa rasc rase rasp rass rbbb rbbr rbbs rbsp rbss rcac rcas rcbc rccb rccc rccs rcep rcga rcgc rcps rcrg rcsa rcsc rcss rea- reac reae reap rear reas reba rebb rebe rebs reca recc rece recp recr recs reeb reep rees rega rege regr regs repe repp repr reps rera rere rerg rers resa rese resp ress rgba rgbe rpca rpcs rpga rpgs rpps rras rrrr rrsp rsaa rscc rscs rsee rsgb rsgc rspb rsps rsre rssa sa-c saab saac saae saag saap saar saas saba sabb sabc sabe sabr sabs saca sacc sace sacr sacs saeb saer saes saga sage sagg sags sapa sape sapp saps sara sarc sare sarg sarp sarr sars sasa sasc sase sass sbaa sbac sbar sbas sbbs sbca sbcc sbcs sber sbsa sbse sbsp scaa scab scac scag scap scar scas scba sccc scce sccp sccs scea scec scee sceg scep scer scgp scgs scpa scpb scpe scps scr- scra scrc scre scrs scsa scsc scsr se-c se-e se-g se-s seaa seab seac seap sear seas seba sebe sebs sec- seca secc sece secg secr secs seea seeb seec seeg seep seer sees sega sege segg segs sepa sepe sepg sepp sepr seps sera serb serc sere serg serp serr sers sesa sesc sese sess sgaa sgac sgap sgca sgcb sgce sgcg sger sges sggg sggs sgps sgss sp-a spac spae spag spap spar spas spca spcc spcs spea speb spec spee speg sper spes spgb spps sprs spsa spse spsp spss sras srbc srcc sreb srec sres srgb srpc srps srsp ssaa ssab ssac ssap ssas ssbr ssca sscc ssce sscp sscs ssec ssee ssep sses ssgs sspa sspc sspe ssps ssra ssrc ssrg ssrs sssa sssb sssc ssss