#nullable enable

#region
var (_input, _iter) = (Array.Empty<string>(), 0);
T I<T>() where T : IParsable<T>
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Trim().Split(' '), 0);
    return T.Parse(_input[_iter++], null);
}
#endregion

static T[] Range<T>(int n, Func<T> F) => Enumerable.Range(0, n).Select(_ => F()).ToArray();

var n = I<int>();
var m = I<int>();
var az = Range(n, () => I<int>() - 1);
var bz = Range(m, I<int>);

var ans = 0;
foreach (var a in az)
{
    if (bz[a] == 0) ans++;
    else bz[a]--;
}
Console.WriteLine(ans);