import java.util.*;

public class Exercise81{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    String weekOne = sc.next();
    String weekTwo = sc.next();

    String twoWeeks = weekOne + weekTwo;
    String[] weekArray = twoWeeks.split("x");

    Arrays.sort(weekArray);

    System.out.println((weekArray.length == 0) ? 0 : weekArray[weekArray.length - 1].length());
  }
}