#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
int main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif
ios::sync_with_stdio(false);
cin.tie(0);
int n, m;
cin >> n >> m;
vector<pair<int, int>> p(n);
for (int i = 0; i < n; ++i)
cin >> p[i].second >> p[i].first;
sort(p.begin(), p.end());
vector<int> c(m);
for (int i = 0; i < m; ++i)
cin >> c[i];
sort(c.begin(), c.end());
int last = m - 1;
for (int i = n - 1; i >= 0; --i) {
if (last >= 0 && p[i].second <= c[last])
--last;
}
cout << m - last - 1 << endl;
return 0;
}
