package yukicode;

import java.util.Scanner;

public class chiwawa {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String input = scanner.nextLine();
		String[] s_array = input.split("");

			int cwwArray[] = new int[3];
			for (int i = 0; i < s_array.length; i++) {
				if (s_array[i].equals("c") && cwwArray[1] == 0) {
					cwwArray[0] = i;
				} else if (s_array[i].equals("w") && cwwArray[1] == 0) {
					cwwArray[1] = i;
				} else if (s_array[i].equals("w") && cwwArray[2] == 0) {
					cwwArray[2] = i;
				}
			}
			if (cwwArray[2] == 0) {
				System.out.println(-1);
			} else {
				System.out.println(cwwArray[2] - cwwArray[0] + 1);
			}
			scanner.close();
	}
}