#include <algorithm>
#include <cassert>
#include <iostream>
#include <variant>
#include <vector>

using namespace std;

int const INF = 2e9;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m;
    cin >> n >> m;

    vector<int> a(n);
    for (int& x : a)
        cin >> x;

    a.insert(a.begin(), 0);
    a.push_back(INF);

    vector<int> b(m);
    for (int& x : b)
        cin >> x;

    sort(b.begin(), b.end());

    int lis_max_len = 0;
    vector<int> lis = { 0 };

    for (int j = 1; j < a.size(); j++) {
        auto it2 = upper_bound(lis.rbegin(), lis.rend(), monostate(), [&](monostate _, int const& i) {
            return a[i] < a[j];
        });

        auto it = find_if_not(it2, lis.rend(), [&](int const& i) {
#ifdef _DEBUG
            cerr << i << " " << j
                << " : " << a[i] << ">=" << a[j]
                << " | " << lower_bound(b.begin(), b.end(), a[j]) - lower_bound(b.begin(), b.end(), a[i]) + 1 << "<" << j - i << endl;
#endif

            return a[i] >= a[j] // not increasing
                || lower_bound(b.begin(), b.end(), a[j]) - lower_bound(b.begin(), b.end(), a[i]) + 1 < j - i; // not enough elements to put between
        });

        if (it == lis.rend())
            continue;

        if (it == lis.rbegin())
            lis.push_back(j);
        else
            *(it - 1) = j;
    }

#ifdef _DEBUG
    assert(count(lis.begin(), lis.end(), n + 1));
#endif

    cout << n - (find(lis.begin(), lis.end(), n + 1) - lis.begin() - 1) << "\n";
}