import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int jack = in.nextInt();
        int jill = in.nextInt();
        int cd;
        AVL tree = new AVL();
        int counter = 0;

        while (jack!=0 && jill!=0) {
            for (int i = 0; i < jack; i++) {
                cd = in.nextInt();
                tree.root = tree.insert(tree.root, cd);
            }

            for (int i = 0; i < jill; i++) {
                cd = in.nextInt();
                boolean finded = tree.find(tree.root, cd);
                if (finded == true) {
                    counter++;
                } else {
                    tree.root = tree.insert(tree.root, cd);
                }
            }

            System.out.println(counter);

            counter = 0;

            jack = in.nextInt();
            jill = in.nextInt();


        }
    }
}

class BSTNode{
    int number;
    int height;
    BSTNode left;
    BSTNode right;


    BSTNode(int num){
        this.number = num;
        this.left = null;
        this.right = null;
        this.height = 0;
    }


}

class AVL{
    BSTNode root;

    AVL(){
        this.root = null;
    }

    public BSTNode insert(BSTNode rt,int num){

        if (rt==null){
            BSTNode node = new BSTNode(num);
            return node;
        }
        if (num<rt.number){
            rt.left = insert(rt.left, num);
        }else if (num>rt.number){
            rt.right = insert(rt.right, num);
        }else{
            rt.right = insert(rt.right, num);
        }

        rt.height = 1 + Math.max(getHeight(rt.left), getHeight(rt.right));
        int balance = getBalance(rt);

        if (balance > 1 && num < rt.left.number) {
            return rightRotate(rt);
        }else if (balance >1 && num >= rt.left.number) {
            rt.left = leftRotate(rt.left);
            return rightRotate(rt);

        }else if (balance < -1 && num >= rt.right.number) {
            return leftRotate(rt);
        }else if (balance <-1 && num <rt.right.number) {
            rt.right = rightRotate(rt.right);
            return leftRotate(rt);
        }

        return rt;

    }


    public int getBalance(BSTNode rt){
        if (rt == null){
            return 0;
        }
        return getHeight(rt.left) - getHeight(rt.right);
    }

    public int getHeight(BSTNode rt){
        if (rt==null){
            return -1;
        }else{
            return rt.height;
        }
    }

    public BSTNode leftRotate(BSTNode rt){

        BSTNode r = rt.right;
        BSTNode rl = r.left;
        r.left = rt;
        rt.right = rl;
        rt.height = Math.max(getHeight(rt.left), getHeight(rt.right)) + 1;
        r.height = Math.max(r.left.height, r.right.height) + 1;

        return r;
    }


    public BSTNode rightRotate(BSTNode rt){

        BSTNode l = rt.left;
        BSTNode lr = l.right;
        l.right = rt;
        rt.left =  lr;
        rt.height = Math.max(getHeight(rt.left), getHeight(rt.right)) + 1;
        l.height = Math.max(getHeight(l.left),getHeight(l.right.left)) + 1;
        return l;
    }

    public boolean find (BSTNode rt, int num){
        if (rt==null){
            return false;
        }else if(rt.number==num){
            return true;
        }else if (num<rt.number){
            return find(rt.left, num);
        }else {
            return find(rt.right, num);
        }
    }

}