import java.util.*;
import java.io.*;

public class cd {
	
	public static void main(String[] args) throws Exception {
		
		BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer tok = new StringTokenizer(stdin.readLine());
		int n = Integer.parseInt(tok.nextToken());
		int m = Integer.parseInt(tok.nextToken());
		
		while (n != 0 || m != 0) {
			
			HashSet<Integer> set = new HashSet<Integer>();
			for (int i=0; i<n; i++)
				set.add(Integer.parseInt(stdin.readLine().trim()));
				
			int res = 0;
			for (int i=0; i<m; i++)
				if (set.contains(Integer.parseInt(stdin.readLine().trim())))
					res++;
				
			System.out.println(res);
			
			tok = new StringTokenizer(stdin.readLine());
			n = Integer.parseInt(tok.nextToken());
			m = Integer.parseInt(tok.nextToken());
		}
	}
}