k-os kkkk kkoo kkot kkov kkss kkst kktk kkts kktv kkvt kkvv kokk koko koks kook kooo koos koot koov kos- koso koss kost kotk koto kots kott kotv kovk kovo kskk ksko ksks ksok ksoo ksos ksso ksss ksst kstk ksto ksts kstt kstv ktkk ktko ktks ktkt ktok ktoo ktot ktso ktst kttk ktto ktts kttt kttv ktvk ktvo ktvt kvok kvoo kvot kvov kvso kvss kvst kvsv kvtk kvto kvtt kvtv kvvs kvvv okko okok okot okso okto oooo ooos oost oots osoo osos osov osso osts oto- otok otoo otos otov otso otto otts ovo- ovoo ovot s-os s-vt skot skov skss sokk soko sook soos soot soso soss sost sosv sotk soto sots sovo sovs ssot ssss ssts st-v stks stok stoo stos stot stss stvs tkos tkts toko took toos toot tosk toso toss tost toto tots tott tovo tsks tsos tsst tsts ttss tttt tvos tvss tvtv voks voot voso voss voto vovk vsto vvvv