import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        String S = sc.next();

        int n = 0;
        boolean c = false;
        int wc = 0;
        for(String s : S.split("")) {
            if (c) n++;
            if (s.equals("c")) {
                n = 1;
                c = true;
            }
            if (s.equals("w")) {
                wc++;
                if (wc == 2) {
                    break;
                }
            }
        }

        if (c && wc == 2) {
            System.out.println(n);
        } else {
            System.out.println("-1");
        }
    }
}