// Arup Guha
// 1/9/2024
// Solution to Kattis Problem: CD
// Used to show how to use Kattis and how to use HashSet.

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

public class cd {

	public static void main(String[] args) throws Exception {

		// Get first n, m.
		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());
		
		// Process all cases.
		while (n!=0 || m!=0) {
			
			// Add all CDs to a set.
			HashSet<Integer> set = new HashSet<Integer>();
			for (int i=0; i<n+m; i++) {
				set.add( Integer.parseInt(stdin.readLine()) );
			}
			
			// Use I/E principle to solve it.
			System.out.println(n+m-set.size());
			
			// Get next case.
			tok = new StringTokenizer(stdin.readLine());
			n = Integer.parseInt(tok.nextToken());
			m = Integer.parseInt(tok.nextToken());
		}
	}
}