import java.util.Scanner;

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

		String s = sc.next();
		int a, b, c;
		a = s.indexOf("c");
		if (a < 0) {
			System.out.println(-1);
			return;
		}
		b = s.indexOf("w", a + 1);
		if (b < 0) {
			System.out.println(-1);
			return;
		}
		c = s.indexOf("w", b + 1);
		if (c < 0) {
			System.out.println(-1);
			return;
		}
		System.out.println(c - a + 1);
	}
}