k-os kkkk kkoo kkov kkpk kkps kksp kkss kkvv kokk koko kokp koks kook kooo koop koos koov kopp kops kos- koso kosp koss kovk kovo kpkk kpok kpoo kpop kppk kppo kppp kppv kpso kpsp kpvs kskk ksko ksks ksok ksoo ksop ksos kspk kspo ksps ksso ksss ksvp kvok kvoo kvop kvov kvps kvso kvsp kvss kvsv kvvp kvvs kvvv okko okok okpo okso oooo ooos oops opo- opos oppo opps osoo osos osov osso ovo- ovoo ovpp poko pook poop poos pop- popo popp pops posk poso poss povo povs ppos pppo pppp ppps ppss psos psov pspp psps psso s-os skop skov skpo skss sokk soko sook soop soos sopo sopp sops soso soss sosv sovo sovs spok spoo spop spos spps spso spsp spss ssop sspo ssps ssss ssvp voks voso voss vovk vsop vvvv