#include <cstdio>
#include <cstring>
#include <iostream>
#include <cmath>
#include <vector>
using namespace std;

long long n,m,a[3000],b[3000],ans = 0,x = 0;
bool used[3000], check;

int main()
{
    cin >> n >> m;

    for (int i = 0; i < n; i++)
        cin >> a[i];
    for (int j = 0; j < m; j++)
        cin >> b[j];


    for (int i=0; i < n; i++)
    {
        check = false;
        for (int j = 0; j < m; j++)
            {
                if (a[i] == b[j] && used[j] == false)
                    {
                        check = true;
                        used[j] = true;
                        break;
                    }
            }

        if (!check)
            ans++;
    }

    cout << ans;


}