import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int c = 0; int w = 0; int indexC = 0; int indexW = 0; int ans = 1001001001;
		for(int i = 0 ; i < s.length() ; i++) {
			if(s.charAt(i) == 'c') {
				c++;
				w = 0;
				indexC = i;
			} else if(s.charAt(i) == 'w') {
				w++;
				if(w == 2) {
					indexW = i;
					ans = Math.min(ans, indexW - indexC + 1);
					indexW = 0; indexC = 0;
				}
			}
		}
		System.out.println(-1);
	}
}