import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String S = sc.next();
        int a =S.indexOf("c");
        if(a==-1){
            System.out.println(-1);
        }else{
            S = S.substring(a);
            int b = S.indexOf("w");
            String t = S.substring(b+1);
            int c = t.indexOf("w");
            if(c==-1){
                System.out.println(-1);
            }else{
                System.out.println(b+c+2);
            }
        }
    }
}