import java.util.*;

class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		
		String[] ar = (sc.next()+sc.next()).split("x",0);
		int max = Integer.MIN_VALUE;
		for (int i=0; i<ar.length; i++) {
			max = Math.max(max, ar[i].length());
		}
		System.out.println(max);
		
	}
}