UVa 11849 - CD

// UVa 11849 - CD

#include <map>
#include <iostream>
#include <stdio.h>
using namespace std;

#define integer unsigned long long

int main() {
	integer n, m;
	while ((cin >> n >> m) && (n || m)) {
		integer a, sol = 0;
		map<integer, bool> mp;
		for (integer i = 0; i < n; i++) {
			scanf("%llu", &a);
			mp[a] = true;
		}
		for (integer i = 0; i < m; i++) {
			scanf("%llu", &a);
			if (mp[a])
				sol++;
		}
		printf("%llu\n", sol);
	}
	return 0;
}