import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String text = scanner.next();
        Pattern p = Pattern.compile("c.*w.*w");
        Matcher m = p.matcher(text);
        int length = Integer.MAX_VALUE;
        while (m.find()) {
            int matched = m.group().length();
            if (length > matched) {
                length = matched;
            }
        }
        if (length == Integer.MAX_VALUE) {
            length = -1;
        }
        System.out.println(length);
    }
}