import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        sc.nextLine();
        char[] arr1 = sc.nextLine().toCharArray();
        char[] arr2 = sc.nextLine().toCharArray();
        boolean prev = true;
        int count = 0;
        for (int i = 0; i < arr1.length; i += 2) {
            boolean current = (arr1[i] == arr2[i]);
            if (prev && !current) {
                count++;
            }
            prev = current;
        }
        System.out.println(count);
    }
}