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 = s.length();
		int ans = 1001001001;
		int w1 = n; int w2 = n;
		for(int i = n - 1 ; i >= 0 ; i--) {
			if(s.charAt(i) == 'w') {
				w2 = w1;
				w1 = i;
			} else if(s.charAt(i) == 'c' && w2 != n){
				ans = Math.min(ans, w2 - i + 1);
			}
		}
		System.out.println(ans == 1001001001 ? -1 : ans);
	}
}