#include <iostream>
using namespace std;
int main()
{
	int n, m,arr1[20],arr2[20];
	cin >> n >> m;
	for (int i = 0; i < n; i++)
	{
		cin >> arr1[i];
	}
	for (int i = 0; i < m; i++)
	{
		cin >> arr2[i];
	}
	int x, y,s=0;
	x = n > m ? n : m;
	y = n > m ? m : n;
	for (int i = 0; i < y; i++)
	{
		for (int j = 0; j < x; j++)
		{
			if (arr1[i] == arr2[j])
			{
				s++;
			}
		}
	}
		
	cout << s;
	return 0;
}