import java.util.Scanner;

public class 随便 {
    public static void main(String[] args) {
        Scanner sca = new Scanner(System.in);
        String str1 = sca.nextLine();
        String str2 = sca.nextLine();
        StringBuffer s1 = new StringBuffer(str1);
        StringBuffer s2 = new StringBuffer(str2);
        int m = 0;

        for (int i = 0; i < s1.length() - 1; i++) {
            if (s1.charAt(i) != s2.charAt(i)) {
            	
                m++;
            	
                if (s1.charAt(i) == '*') 
                    s1.setCharAt(i, 'o');
                else 
                    s1.setCharAt(i, '*');
                
                if (s1.charAt(i + 1) == '*') 
                    s1.setCharAt(i + 1, 'o');
                else
                    s1.setCharAt(i + 1, '*');
                
            }
        }

        System.out.println(m); // 打印结果或进行其他操作
    }
}

大佬这哪里有问题