class No345 {
	public static void main(String[] args) {
		String s = args[0];
		String[] s_array = s.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);
		}
	}
}